diff --git a/README.md b/README.md
index abed0c84..e86aed1d 100644
--- a/README.md
+++ b/README.md
@@ -57,13 +57,13 @@ implementation 'com.google.cloud:google-cloud-texttospeech'
 If you are using Gradle without BOM, add this to your dependencies:
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-texttospeech:2.4.7'
+implementation 'com.google.cloud:google-cloud-texttospeech:2.4.8'
 ```
 
 If you are using SBT, add this to your dependencies:
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-texttospeech" % "2.4.7"
+libraryDependencies += "com.google.cloud" % "google-cloud-texttospeech" % "2.4.8"
 ```
 
 ## Authentication
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/AudioConfig.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/AudioConfig.java
index d753f292..8a0b42a3 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/AudioConfig.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/AudioConfig.java
@@ -53,86 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private AudioConfig(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 8:
-            {
-              int rawValue = input.readEnum();
-
-              audioEncoding_ = rawValue;
-              break;
-            }
-          case 17:
-            {
-              speakingRate_ = input.readDouble();
-              break;
-            }
-          case 25:
-            {
-              pitch_ = input.readDouble();
-              break;
-            }
-          case 33:
-            {
-              volumeGainDb_ = input.readDouble();
-              break;
-            }
-          case 40:
-            {
-              sampleRateHertz_ = input.readInt32();
-              break;
-            }
-          case 50:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                effectsProfileId_ = new com.google.protobuf.LazyStringArrayList();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              effectsProfileId_.add(s);
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        effectsProfileId_ = effectsProfileId_.getUnmodifiableView();
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_AudioConfig_descriptor;
@@ -406,7 +326,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < effectsProfileId_.size(); i++) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 6, effectsProfileId_.getRaw(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -439,7 +359,7 @@ public int getSerializedSize() {
       size += dataSize;
       size += 1 * getEffectsProfileIdList().size();
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -464,7 +384,7 @@ public boolean equals(final java.lang.Object obj) {
         != java.lang.Double.doubleToLongBits(other.getVolumeGainDb())) return false;
     if (getSampleRateHertz() != other.getSampleRateHertz()) return false;
     if (!getEffectsProfileIdList().equals(other.getEffectsProfileIdList())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -497,7 +417,7 @@ public int hashCode() {
       hash = (37 * hash) + EFFECTS_PROFILE_ID_FIELD_NUMBER;
       hash = (53 * hash) + getEffectsProfileIdList().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -626,17 +546,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.AudioConfig.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -766,7 +679,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.AudioConfig other) {
         }
         onChanged();
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -781,17 +694,68 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.AudioConfig parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 8:
+              {
+                audioEncoding_ = input.readEnum();
+
+                break;
+              } // case 8
+            case 17:
+              {
+                speakingRate_ = input.readDouble();
+
+                break;
+              } // case 17
+            case 25:
+              {
+                pitch_ = input.readDouble();
+
+                break;
+              } // case 25
+            case 33:
+              {
+                volumeGainDb_ = input.readDouble();
+
+                break;
+              } // case 33
+            case 40:
+              {
+                sampleRateHertz_ = input.readInt32();
+
+                break;
+              } // case 40
+            case 50:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                ensureEffectsProfileIdIsMutable();
+                effectsProfileId_.add(s);
+                break;
+              } // case 50
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage = (com.google.cloud.texttospeech.v1.AudioConfig) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1441,7 +1405,18 @@ public AudioConfig parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new AudioConfig(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/CustomVoiceParams.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/CustomVoiceParams.java
index 0d890006..3473caf0 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/CustomVoiceParams.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/CustomVoiceParams.java
@@ -53,59 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private CustomVoiceParams(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              model_ = s;
-              break;
-            }
-          case 24:
-            {
-              int rawValue = input.readEnum();
-
-              reportedUsage_ = rawValue;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_CustomVoiceParams_descriptor;
@@ -406,7 +353,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
             .getNumber()) {
       output.writeEnum(3, reportedUsage_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -424,7 +371,7 @@ public int getSerializedSize() {
             .getNumber()) {
       size += com.google.protobuf.CodedOutputStream.computeEnumSize(3, reportedUsage_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -442,7 +389,7 @@ public boolean equals(final java.lang.Object obj) {
 
     if (!getModel().equals(other.getModel())) return false;
     if (reportedUsage_ != other.reportedUsage_) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -457,7 +404,7 @@ public int hashCode() {
     hash = (53 * hash) + getModel().hashCode();
     hash = (37 * hash) + REPORTED_USAGE_FIELD_NUMBER;
     hash = (53 * hash) + reportedUsage_;
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -586,17 +533,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.CustomVoiceParams.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -692,7 +632,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.CustomVoiceParams othe
       if (other.reportedUsage_ != 0) {
         setReportedUsageValue(other.getReportedUsageValue());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -707,18 +647,43 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.CustomVoiceParams parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                model_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            case 24:
+              {
+                reportedUsage_ = input.readEnum();
+
+                break;
+              } // case 24
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1.CustomVoiceParams) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -974,7 +939,18 @@ public CustomVoiceParams parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new CustomVoiceParams(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesRequest.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesRequest.java
index ea839dcd..a000fc81 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesRequest.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesRequest.java
@@ -52,52 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private ListVoicesRequest(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              languageCode_ = s;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_ListVoicesRequest_descriptor;
@@ -193,7 +147,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(languageCode_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 1, languageCode_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -205,7 +159,7 @@ public int getSerializedSize() {
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(languageCode_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, languageCode_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -222,7 +176,7 @@ public boolean equals(final java.lang.Object obj) {
         (com.google.cloud.texttospeech.v1.ListVoicesRequest) obj;
 
     if (!getLanguageCode().equals(other.getLanguageCode())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -235,7 +189,7 @@ public int hashCode() {
     hash = (19 * hash) + getDescriptor().hashCode();
     hash = (37 * hash) + LANGUAGE_CODE_FIELD_NUMBER;
     hash = (53 * hash) + getLanguageCode().hashCode();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -364,17 +318,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.ListVoicesRequest.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -464,7 +411,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.ListVoicesRequest othe
         languageCode_ = other.languageCode_;
         onChanged();
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -479,18 +426,37 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.ListVoicesRequest parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                languageCode_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1.ListVoicesRequest) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -667,7 +633,18 @@ public ListVoicesRequest parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new ListVoicesRequest(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesResponse.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesResponse.java
index 30f15ed6..79feb983 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesResponse.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/ListVoicesResponse.java
@@ -52,60 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private ListVoicesResponse(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                voices_ = new java.util.ArrayList<com.google.cloud.texttospeech.v1.Voice>();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              voices_.add(
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1.Voice.parser(), extensionRegistry));
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        voices_ = java.util.Collections.unmodifiableList(voices_);
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_ListVoicesResponse_descriptor;
@@ -207,7 +153,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < voices_.size(); i++) {
       output.writeMessage(1, voices_.get(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -219,7 +165,7 @@ public int getSerializedSize() {
     for (int i = 0; i < voices_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(1, voices_.get(i));
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -236,7 +182,7 @@ public boolean equals(final java.lang.Object obj) {
         (com.google.cloud.texttospeech.v1.ListVoicesResponse) obj;
 
     if (!getVoicesList().equals(other.getVoicesList())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -251,7 +197,7 @@ public int hashCode() {
       hash = (37 * hash) + VOICES_FIELD_NUMBER;
       hash = (53 * hash) + getVoicesList().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -380,19 +326,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.ListVoicesResponse.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
-        getVoicesFieldBuilder();
-      }
     }
 
     @java.lang.Override
@@ -400,10 +337,11 @@ public Builder clear() {
       super.clear();
       if (voicesBuilder_ == null) {
         voices_ = java.util.Collections.emptyList();
-        bitField0_ = (bitField0_ & ~0x00000001);
       } else {
+        voices_ = null;
         voicesBuilder_.clear();
       }
+      bitField0_ = (bitField0_ & ~0x00000001);
       return this;
     }
 
@@ -518,7 +456,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.ListVoicesResponse oth
           }
         }
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -533,18 +471,44 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.ListVoicesResponse parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                com.google.cloud.texttospeech.v1.Voice m =
+                    input.readMessage(
+                        com.google.cloud.texttospeech.v1.Voice.parser(), extensionRegistry);
+                if (voicesBuilder_ == null) {
+                  ensureVoicesIsMutable();
+                  voices_.add(m);
+                } else {
+                  voicesBuilder_.addMessage(m);
+                }
+                break;
+              } // case 10
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1.ListVoicesResponse) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -930,7 +894,18 @@ public ListVoicesResponse parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new ListVoicesResponse(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesisInput.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesisInput.java
index 5509d11a..f2811303 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesisInput.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesisInput.java
@@ -53,59 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private SynthesisInput(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              inputSourceCase_ = 1;
-              inputSource_ = s;
-              break;
-            }
-          case 18:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              inputSourceCase_ = 2;
-              inputSource_ = s;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_SynthesisInput_descriptor;
@@ -337,7 +284,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (inputSourceCase_ == 2) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 2, inputSource_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -352,7 +299,7 @@ public int getSerializedSize() {
     if (inputSourceCase_ == 2) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, inputSource_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -379,7 +326,7 @@ public boolean equals(final java.lang.Object obj) {
       case 0:
       default:
     }
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -402,7 +349,7 @@ public int hashCode() {
       case 0:
       default:
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -534,17 +481,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.SynthesisInput.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -656,7 +596,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.SynthesisInput other)
             break;
           }
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -671,17 +611,45 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.SynthesisInput parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                inputSourceCase_ = 1;
+                inputSource_ = s;
+                break;
+              } // case 10
+            case 18:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                inputSourceCase_ = 2;
+                inputSource_ = s;
+                break;
+              } // case 18
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage = (com.google.cloud.texttospeech.v1.SynthesisInput) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1017,7 +985,18 @@ public SynthesisInput parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new SynthesisInput(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechRequest.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechRequest.java
index f5e20bcd..4de5922c 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechRequest.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechRequest.java
@@ -50,94 +50,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private SynthesizeSpeechRequest(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              com.google.cloud.texttospeech.v1.SynthesisInput.Builder subBuilder = null;
-              if (input_ != null) {
-                subBuilder = input_.toBuilder();
-              }
-              input_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1.SynthesisInput.parser(), extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(input_);
-                input_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          case 18:
-            {
-              com.google.cloud.texttospeech.v1.VoiceSelectionParams.Builder subBuilder = null;
-              if (voice_ != null) {
-                subBuilder = voice_.toBuilder();
-              }
-              voice_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1.VoiceSelectionParams.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(voice_);
-                voice_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          case 26:
-            {
-              com.google.cloud.texttospeech.v1.AudioConfig.Builder subBuilder = null;
-              if (audioConfig_ != null) {
-                subBuilder = audioConfig_.toBuilder();
-              }
-              audioConfig_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1.AudioConfig.parser(), extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(audioConfig_);
-                audioConfig_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_SynthesizeSpeechRequest_descriptor;
@@ -338,7 +250,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (audioConfig_ != null) {
       output.writeMessage(3, getAudioConfig());
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -356,7 +268,7 @@ public int getSerializedSize() {
     if (audioConfig_ != null) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(3, getAudioConfig());
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -384,7 +296,7 @@ public boolean equals(final java.lang.Object obj) {
     if (hasAudioConfig()) {
       if (!getAudioConfig().equals(other.getAudioConfig())) return false;
     }
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -407,7 +319,7 @@ public int hashCode() {
       hash = (37 * hash) + AUDIO_CONFIG_FIELD_NUMBER;
       hash = (53 * hash) + getAudioConfig().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -537,17 +449,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.SynthesizeSpeechRequest.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -672,7 +577,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.SynthesizeSpeechReques
       if (other.hasAudioConfig()) {
         mergeAudioConfig(other.getAudioConfig());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -687,18 +592,49 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.SynthesizeSpeechRequest parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                input.readMessage(getInputFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 10
+            case 18:
+              {
+                input.readMessage(getVoiceFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 18
+            case 26:
+              {
+                input.readMessage(getAudioConfigFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 26
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1.SynthesizeSpeechRequest) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1346,7 +1282,18 @@ public SynthesizeSpeechRequest parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new SynthesizeSpeechRequest(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechResponse.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechResponse.java
index 11e69a04..89f8a36d 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechResponse.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechResponse.java
@@ -52,50 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private SynthesizeSpeechResponse(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              audioContent_ = input.readBytes();
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_SynthesizeSpeechResponse_descriptor;
@@ -150,7 +106,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (!audioContent_.isEmpty()) {
       output.writeBytes(1, audioContent_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -162,7 +118,7 @@ public int getSerializedSize() {
     if (!audioContent_.isEmpty()) {
       size += com.google.protobuf.CodedOutputStream.computeBytesSize(1, audioContent_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -179,7 +135,7 @@ public boolean equals(final java.lang.Object obj) {
         (com.google.cloud.texttospeech.v1.SynthesizeSpeechResponse) obj;
 
     if (!getAudioContent().equals(other.getAudioContent())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -192,7 +148,7 @@ public int hashCode() {
     hash = (19 * hash) + getDescriptor().hashCode();
     hash = (37 * hash) + AUDIO_CONTENT_FIELD_NUMBER;
     hash = (53 * hash) + getAudioContent().hashCode();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -322,17 +278,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.SynthesizeSpeechResponse.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -421,7 +370,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.SynthesizeSpeechRespon
       if (other.getAudioContent() != com.google.protobuf.ByteString.EMPTY) {
         setAudioContent(other.getAudioContent());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -436,18 +385,37 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.SynthesizeSpeechResponse parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                audioContent_ = input.readBytes();
+
+                break;
+              } // case 10
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1.SynthesizeSpeechResponse) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -550,7 +518,18 @@ public SynthesizeSpeechResponse parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new SynthesizeSpeechResponse(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/Voice.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/Voice.java
index ef13ce22..ba50be69 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/Voice.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/Voice.java
@@ -54,78 +54,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private Voice(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                languageCodes_ = new com.google.protobuf.LazyStringArrayList();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              languageCodes_.add(s);
-              break;
-            }
-          case 18:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              name_ = s;
-              break;
-            }
-          case 24:
-            {
-              int rawValue = input.readEnum();
-
-              ssmlGender_ = rawValue;
-              break;
-            }
-          case 32:
-            {
-              naturalSampleRateHertz_ = input.readInt32();
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        languageCodes_ = languageCodes_.getUnmodifiableView();
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_Voice_descriptor;
@@ -341,7 +269,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (naturalSampleRateHertz_ != 0) {
       output.writeInt32(4, naturalSampleRateHertz_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -369,7 +297,7 @@ public int getSerializedSize() {
     if (naturalSampleRateHertz_ != 0) {
       size += com.google.protobuf.CodedOutputStream.computeInt32Size(4, naturalSampleRateHertz_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -388,7 +316,7 @@ public boolean equals(final java.lang.Object obj) {
     if (!getName().equals(other.getName())) return false;
     if (ssmlGender_ != other.ssmlGender_) return false;
     if (getNaturalSampleRateHertz() != other.getNaturalSampleRateHertz()) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -409,7 +337,7 @@ public int hashCode() {
     hash = (53 * hash) + ssmlGender_;
     hash = (37 * hash) + NATURAL_SAMPLE_RATE_HERTZ_FIELD_NUMBER;
     hash = (53 * hash) + getNaturalSampleRateHertz();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -538,17 +466,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.Voice.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -667,7 +588,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.Voice other) {
       if (other.getNaturalSampleRateHertz() != 0) {
         setNaturalSampleRateHertz(other.getNaturalSampleRateHertz());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -682,17 +603,56 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.Voice parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                ensureLanguageCodesIsMutable();
+                languageCodes_.add(s);
+                break;
+              } // case 10
+            case 18:
+              {
+                name_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 18
+            case 24:
+              {
+                ssmlGender_ = input.readEnum();
+
+                break;
+              } // case 24
+            case 32:
+              {
+                naturalSampleRateHertz_ = input.readInt32();
+
+                break;
+              } // case 32
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage = (com.google.cloud.texttospeech.v1.Voice) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1167,7 +1127,18 @@ public Voice parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new Voice(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/VoiceSelectionParams.java b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/VoiceSelectionParams.java
index 7c5a4b4e..c54974f1 100644
--- a/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/VoiceSelectionParams.java
+++ b/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/VoiceSelectionParams.java
@@ -54,83 +54,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private VoiceSelectionParams(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              languageCode_ = s;
-              break;
-            }
-          case 18:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              name_ = s;
-              break;
-            }
-          case 24:
-            {
-              int rawValue = input.readEnum();
-
-              ssmlGender_ = rawValue;
-              break;
-            }
-          case 34:
-            {
-              com.google.cloud.texttospeech.v1.CustomVoiceParams.Builder subBuilder = null;
-              if (customVoice_ != null) {
-                subBuilder = customVoice_.toBuilder();
-              }
-              customVoice_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1.CustomVoiceParams.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(customVoice_);
-                customVoice_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1_VoiceSelectionParams_descriptor;
@@ -392,7 +315,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (customVoice_ != null) {
       output.writeMessage(4, getCustomVoice());
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -415,7 +338,7 @@ public int getSerializedSize() {
     if (customVoice_ != null) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(4, getCustomVoice());
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -438,7 +361,7 @@ public boolean equals(final java.lang.Object obj) {
     if (hasCustomVoice()) {
       if (!getCustomVoice().equals(other.getCustomVoice())) return false;
     }
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -459,7 +382,7 @@ public int hashCode() {
       hash = (37 * hash) + CUSTOM_VOICE_FIELD_NUMBER;
       hash = (53 * hash) + getCustomVoice().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -589,17 +512,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1.VoiceSelectionParams.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -716,7 +632,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1.VoiceSelectionParams o
       if (other.hasCustomVoice()) {
         mergeCustomVoice(other.getCustomVoice());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -731,18 +647,55 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1.VoiceSelectionParams parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                languageCode_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            case 18:
+              {
+                name_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 18
+            case 24:
+              {
+                ssmlGender_ = input.readEnum();
+
+                break;
+              } // case 24
+            case 34:
+              {
+                input.readMessage(getCustomVoiceFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 34
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1.VoiceSelectionParams) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1362,7 +1315,18 @@ public VoiceSelectionParams parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new VoiceSelectionParams(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/AudioConfig.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/AudioConfig.java
index 50722bdf..c7a8ef53 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/AudioConfig.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/AudioConfig.java
@@ -53,86 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private AudioConfig(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 8:
-            {
-              int rawValue = input.readEnum();
-
-              audioEncoding_ = rawValue;
-              break;
-            }
-          case 17:
-            {
-              speakingRate_ = input.readDouble();
-              break;
-            }
-          case 25:
-            {
-              pitch_ = input.readDouble();
-              break;
-            }
-          case 33:
-            {
-              volumeGainDb_ = input.readDouble();
-              break;
-            }
-          case 40:
-            {
-              sampleRateHertz_ = input.readInt32();
-              break;
-            }
-          case 50:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                effectsProfileId_ = new com.google.protobuf.LazyStringArrayList();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              effectsProfileId_.add(s);
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        effectsProfileId_ = effectsProfileId_.getUnmodifiableView();
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_AudioConfig_descriptor;
@@ -409,7 +329,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < effectsProfileId_.size(); i++) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 6, effectsProfileId_.getRaw(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -443,7 +363,7 @@ public int getSerializedSize() {
       size += dataSize;
       size += 1 * getEffectsProfileIdList().size();
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -468,7 +388,7 @@ public boolean equals(final java.lang.Object obj) {
         != java.lang.Double.doubleToLongBits(other.getVolumeGainDb())) return false;
     if (getSampleRateHertz() != other.getSampleRateHertz()) return false;
     if (!getEffectsProfileIdList().equals(other.getEffectsProfileIdList())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -501,7 +421,7 @@ public int hashCode() {
       hash = (37 * hash) + EFFECTS_PROFILE_ID_FIELD_NUMBER;
       hash = (53 * hash) + getEffectsProfileIdList().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -630,17 +550,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.AudioConfig.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -771,7 +684,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.AudioConfig other
         }
         onChanged();
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -786,18 +699,68 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.AudioConfig parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 8:
+              {
+                audioEncoding_ = input.readEnum();
+
+                break;
+              } // case 8
+            case 17:
+              {
+                speakingRate_ = input.readDouble();
+
+                break;
+              } // case 17
+            case 25:
+              {
+                pitch_ = input.readDouble();
+
+                break;
+              } // case 25
+            case 33:
+              {
+                volumeGainDb_ = input.readDouble();
+
+                break;
+              } // case 33
+            case 40:
+              {
+                sampleRateHertz_ = input.readInt32();
+
+                break;
+              } // case 40
+            case 50:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                ensureEffectsProfileIdIsMutable();
+                effectsProfileId_.add(s);
+                break;
+              } // case 50
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.AudioConfig) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1449,7 +1412,18 @@ public AudioConfig parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new AudioConfig(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/CustomVoiceParams.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/CustomVoiceParams.java
index 794e11e6..2039d006 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/CustomVoiceParams.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/CustomVoiceParams.java
@@ -53,59 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private CustomVoiceParams(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              model_ = s;
-              break;
-            }
-          case 24:
-            {
-              int rawValue = input.readEnum();
-
-              reportedUsage_ = rawValue;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_CustomVoiceParams_descriptor;
@@ -407,7 +354,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
             .getNumber()) {
       output.writeEnum(3, reportedUsage_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -425,7 +372,7 @@ public int getSerializedSize() {
             .getNumber()) {
       size += com.google.protobuf.CodedOutputStream.computeEnumSize(3, reportedUsage_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -443,7 +390,7 @@ public boolean equals(final java.lang.Object obj) {
 
     if (!getModel().equals(other.getModel())) return false;
     if (reportedUsage_ != other.reportedUsage_) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -458,7 +405,7 @@ public int hashCode() {
     hash = (53 * hash) + getModel().hashCode();
     hash = (37 * hash) + REPORTED_USAGE_FIELD_NUMBER;
     hash = (53 * hash) + reportedUsage_;
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -588,17 +535,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.CustomVoiceParams.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -694,7 +634,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.CustomVoiceParams
       if (other.reportedUsage_ != 0) {
         setReportedUsageValue(other.getReportedUsageValue());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -709,18 +649,43 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.CustomVoiceParams parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                model_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            case 24:
+              {
+                reportedUsage_ = input.readEnum();
+
+                break;
+              } // case 24
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.CustomVoiceParams) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -978,7 +943,18 @@ public CustomVoiceParams parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new CustomVoiceParams(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesRequest.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesRequest.java
index 41103ee3..a06d998f 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesRequest.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesRequest.java
@@ -52,52 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private ListVoicesRequest(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              languageCode_ = s;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_ListVoicesRequest_descriptor;
@@ -193,7 +147,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(languageCode_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 1, languageCode_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -205,7 +159,7 @@ public int getSerializedSize() {
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(languageCode_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, languageCode_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -222,7 +176,7 @@ public boolean equals(final java.lang.Object obj) {
         (com.google.cloud.texttospeech.v1beta1.ListVoicesRequest) obj;
 
     if (!getLanguageCode().equals(other.getLanguageCode())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -235,7 +189,7 @@ public int hashCode() {
     hash = (19 * hash) + getDescriptor().hashCode();
     hash = (37 * hash) + LANGUAGE_CODE_FIELD_NUMBER;
     hash = (53 * hash) + getLanguageCode().hashCode();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -365,17 +319,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.ListVoicesRequest.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -465,7 +412,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.ListVoicesRequest
         languageCode_ = other.languageCode_;
         onChanged();
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -480,18 +427,37 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.ListVoicesRequest parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                languageCode_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.ListVoicesRequest) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -668,7 +634,18 @@ public ListVoicesRequest parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new ListVoicesRequest(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesResponse.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesResponse.java
index d3ba67aa..d7fdd7cc 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesResponse.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/ListVoicesResponse.java
@@ -52,60 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private ListVoicesResponse(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                voices_ = new java.util.ArrayList<com.google.cloud.texttospeech.v1beta1.Voice>();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              voices_.add(
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.Voice.parser(), extensionRegistry));
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        voices_ = java.util.Collections.unmodifiableList(voices_);
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_ListVoicesResponse_descriptor;
@@ -207,7 +153,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < voices_.size(); i++) {
       output.writeMessage(1, voices_.get(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -219,7 +165,7 @@ public int getSerializedSize() {
     for (int i = 0; i < voices_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(1, voices_.get(i));
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -236,7 +182,7 @@ public boolean equals(final java.lang.Object obj) {
         (com.google.cloud.texttospeech.v1beta1.ListVoicesResponse) obj;
 
     if (!getVoicesList().equals(other.getVoicesList())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -251,7 +197,7 @@ public int hashCode() {
       hash = (37 * hash) + VOICES_FIELD_NUMBER;
       hash = (53 * hash) + getVoicesList().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -381,19 +327,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.ListVoicesResponse.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
-        getVoicesFieldBuilder();
-      }
     }
 
     @java.lang.Override
@@ -401,10 +338,11 @@ public Builder clear() {
       super.clear();
       if (voicesBuilder_ == null) {
         voices_ = java.util.Collections.emptyList();
-        bitField0_ = (bitField0_ & ~0x00000001);
       } else {
+        voices_ = null;
         voicesBuilder_.clear();
       }
+      bitField0_ = (bitField0_ & ~0x00000001);
       return this;
     }
 
@@ -519,7 +457,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.ListVoicesRespons
           }
         }
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -534,18 +472,44 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.ListVoicesResponse parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                com.google.cloud.texttospeech.v1beta1.Voice m =
+                    input.readMessage(
+                        com.google.cloud.texttospeech.v1beta1.Voice.parser(), extensionRegistry);
+                if (voicesBuilder_ == null) {
+                  ensureVoicesIsMutable();
+                  voices_.add(m);
+                } else {
+                  voicesBuilder_.addMessage(m);
+                }
+                break;
+              } // case 10
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.ListVoicesResponse) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -932,7 +896,18 @@ public ListVoicesResponse parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new ListVoicesResponse(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesisInput.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesisInput.java
index 260a2a19..951558f9 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesisInput.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesisInput.java
@@ -53,59 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private SynthesisInput(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              inputSourceCase_ = 1;
-              inputSource_ = s;
-              break;
-            }
-          case 18:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              inputSourceCase_ = 2;
-              inputSource_ = s;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_SynthesisInput_descriptor;
@@ -337,7 +284,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (inputSourceCase_ == 2) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 2, inputSource_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -352,7 +299,7 @@ public int getSerializedSize() {
     if (inputSourceCase_ == 2) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, inputSource_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -379,7 +326,7 @@ public boolean equals(final java.lang.Object obj) {
       case 0:
       default:
     }
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -402,7 +349,7 @@ public int hashCode() {
       case 0:
       default:
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -534,17 +481,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.SynthesisInput.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -656,7 +596,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.SynthesisInput ot
             break;
           }
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -671,18 +611,45 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.SynthesisInput parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                inputSourceCase_ = 1;
+                inputSource_ = s;
+                break;
+              } // case 10
+            case 18:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                inputSourceCase_ = 2;
+                inputSource_ = s;
+                break;
+              } // case 18
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.SynthesisInput) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1018,7 +985,18 @@ public SynthesisInput parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new SynthesisInput(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechRequest.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechRequest.java
index 3c43505f..a1b09623 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechRequest.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechRequest.java
@@ -52,125 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private SynthesizeSpeechRequest(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              com.google.cloud.texttospeech.v1beta1.SynthesisInput.Builder subBuilder = null;
-              if (input_ != null) {
-                subBuilder = input_.toBuilder();
-              }
-              input_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.SynthesisInput.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(input_);
-                input_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          case 18:
-            {
-              com.google.cloud.texttospeech.v1beta1.VoiceSelectionParams.Builder subBuilder = null;
-              if (voice_ != null) {
-                subBuilder = voice_.toBuilder();
-              }
-              voice_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.VoiceSelectionParams.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(voice_);
-                voice_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          case 26:
-            {
-              com.google.cloud.texttospeech.v1beta1.AudioConfig.Builder subBuilder = null;
-              if (audioConfig_ != null) {
-                subBuilder = audioConfig_.toBuilder();
-              }
-              audioConfig_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.AudioConfig.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(audioConfig_);
-                audioConfig_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          case 32:
-            {
-              int rawValue = input.readEnum();
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                enableTimePointing_ = new java.util.ArrayList<java.lang.Integer>();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              enableTimePointing_.add(rawValue);
-              break;
-            }
-          case 34:
-            {
-              int length = input.readRawVarint32();
-              int oldLimit = input.pushLimit(length);
-              while (input.getBytesUntilLimit() > 0) {
-                int rawValue = input.readEnum();
-                if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                  enableTimePointing_ = new java.util.ArrayList<java.lang.Integer>();
-                  mutable_bitField0_ |= 0x00000001;
-                }
-                enableTimePointing_.add(rawValue);
-              }
-              input.popLimit(oldLimit);
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        enableTimePointing_ = java.util.Collections.unmodifiableList(enableTimePointing_);
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_SynthesizeSpeechRequest_descriptor;
@@ -632,7 +513,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < enableTimePointing_.size(); i++) {
       output.writeEnumNoTag(enableTimePointing_.get(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -663,7 +544,7 @@ public int getSerializedSize() {
       }
       enableTimePointingMemoizedSerializedSize = dataSize;
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -692,7 +573,7 @@ public boolean equals(final java.lang.Object obj) {
       if (!getAudioConfig().equals(other.getAudioConfig())) return false;
     }
     if (!enableTimePointing_.equals(other.enableTimePointing_)) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -719,7 +600,7 @@ public int hashCode() {
       hash = (37 * hash) + ENABLE_TIME_POINTING_FIELD_NUMBER;
       hash = (53 * hash) + enableTimePointing_.hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -849,17 +730,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechRequest.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -1004,7 +878,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechR
         }
         onChanged();
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -1019,19 +893,68 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechRequest parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                input.readMessage(getInputFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 10
+            case 18:
+              {
+                input.readMessage(getVoiceFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 18
+            case 26:
+              {
+                input.readMessage(getAudioConfigFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 26
+            case 32:
+              {
+                int tmpRaw = input.readEnum();
+                ensureEnableTimePointingIsMutable();
+                enableTimePointing_.add(tmpRaw);
+                break;
+              } // case 32
+            case 34:
+              {
+                int length = input.readRawVarint32();
+                int oldLimit = input.pushLimit(length);
+                while (input.getBytesUntilLimit() > 0) {
+                  int tmpRaw = input.readEnum();
+                  ensureEnableTimePointingIsMutable();
+                  enableTimePointing_.add(tmpRaw);
+                }
+                input.popLimit(oldLimit);
+                break;
+              } // case 34
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechRequest)
-                e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1939,7 +1862,18 @@ public SynthesizeSpeechRequest parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new SynthesizeSpeechRequest(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechResponse.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechResponse.java
index 33386178..ab6e8e51 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechResponse.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechResponse.java
@@ -53,83 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private SynthesizeSpeechResponse(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              audioContent_ = input.readBytes();
-              break;
-            }
-          case 18:
-            {
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                timepoints_ =
-                    new java.util.ArrayList<com.google.cloud.texttospeech.v1beta1.Timepoint>();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              timepoints_.add(
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.Timepoint.parser(), extensionRegistry));
-              break;
-            }
-          case 34:
-            {
-              com.google.cloud.texttospeech.v1beta1.AudioConfig.Builder subBuilder = null;
-              if (audioConfig_ != null) {
-                subBuilder = audioConfig_.toBuilder();
-              }
-              audioConfig_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.AudioConfig.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(audioConfig_);
-                audioConfig_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        timepoints_ = java.util.Collections.unmodifiableList(timepoints_);
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_SynthesizeSpeechResponse_descriptor;
@@ -313,7 +236,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (audioConfig_ != null) {
       output.writeMessage(4, getAudioConfig());
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -331,7 +254,7 @@ public int getSerializedSize() {
     if (audioConfig_ != null) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(4, getAudioConfig());
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -353,7 +276,7 @@ public boolean equals(final java.lang.Object obj) {
     if (hasAudioConfig()) {
       if (!getAudioConfig().equals(other.getAudioConfig())) return false;
     }
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -374,7 +297,7 @@ public int hashCode() {
       hash = (37 * hash) + AUDIO_CONFIG_FIELD_NUMBER;
       hash = (53 * hash) + getAudioConfig().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -504,19 +427,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechResponse.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
-        getTimepointsFieldBuilder();
-      }
     }
 
     @java.lang.Override
@@ -526,10 +440,11 @@ public Builder clear() {
 
       if (timepointsBuilder_ == null) {
         timepoints_ = java.util.Collections.emptyList();
-        bitField0_ = (bitField0_ & ~0x00000001);
       } else {
+        timepoints_ = null;
         timepointsBuilder_.clear();
       }
+      bitField0_ = (bitField0_ & ~0x00000001);
       if (audioConfigBuilder_ == null) {
         audioConfig_ = null;
       } else {
@@ -664,7 +579,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechR
       if (other.hasAudioConfig()) {
         mergeAudioConfig(other.getAudioConfig());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -679,19 +594,57 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechResponse parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                audioContent_ = input.readBytes();
+
+                break;
+              } // case 10
+            case 18:
+              {
+                com.google.cloud.texttospeech.v1beta1.Timepoint m =
+                    input.readMessage(
+                        com.google.cloud.texttospeech.v1beta1.Timepoint.parser(),
+                        extensionRegistry);
+                if (timepointsBuilder_ == null) {
+                  ensureTimepointsIsMutable();
+                  timepoints_.add(m);
+                } else {
+                  timepointsBuilder_.addMessage(m);
+                }
+                break;
+              } // case 18
+            case 34:
+              {
+                input.readMessage(getAudioConfigFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 34
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.SynthesizeSpeechResponse)
-                e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1354,7 +1307,18 @@ public SynthesizeSpeechResponse parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new SynthesizeSpeechResponse(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Timepoint.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Timepoint.java
index 8b114202..186abb28 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Timepoint.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Timepoint.java
@@ -53,57 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private Timepoint(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 25:
-            {
-              timeSeconds_ = input.readDouble();
-              break;
-            }
-          case 34:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              markName_ = s;
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_Timepoint_descriptor;
@@ -206,7 +155,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(markName_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 4, markName_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -221,7 +170,7 @@ public int getSerializedSize() {
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(markName_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, markName_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -240,7 +189,7 @@ public boolean equals(final java.lang.Object obj) {
     if (!getMarkName().equals(other.getMarkName())) return false;
     if (java.lang.Double.doubleToLongBits(getTimeSeconds())
         != java.lang.Double.doubleToLongBits(other.getTimeSeconds())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -258,7 +207,7 @@ public int hashCode() {
         (53 * hash)
             + com.google.protobuf.Internal.hashLong(
                 java.lang.Double.doubleToLongBits(getTimeSeconds()));
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -388,17 +337,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.Timepoint.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -494,7 +436,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.Timepoint other)
       if (other.getTimeSeconds() != 0D) {
         setTimeSeconds(other.getTimeSeconds());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -509,17 +451,43 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.Timepoint parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 25:
+              {
+                timeSeconds_ = input.readDouble();
+
+                break;
+              } // case 25
+            case 34:
+              {
+                markName_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 34
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage = (com.google.cloud.texttospeech.v1beta1.Timepoint) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -713,7 +681,18 @@ public Timepoint parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new Timepoint(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Voice.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Voice.java
index b1c4fe78..c64d6369 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Voice.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Voice.java
@@ -54,78 +54,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private Voice(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                languageCodes_ = new com.google.protobuf.LazyStringArrayList();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              languageCodes_.add(s);
-              break;
-            }
-          case 18:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              name_ = s;
-              break;
-            }
-          case 24:
-            {
-              int rawValue = input.readEnum();
-
-              ssmlGender_ = rawValue;
-              break;
-            }
-          case 32:
-            {
-              naturalSampleRateHertz_ = input.readInt32();
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        languageCodes_ = languageCodes_.getUnmodifiableView();
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_Voice_descriptor;
@@ -343,7 +271,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (naturalSampleRateHertz_ != 0) {
       output.writeInt32(4, naturalSampleRateHertz_);
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -371,7 +299,7 @@ public int getSerializedSize() {
     if (naturalSampleRateHertz_ != 0) {
       size += com.google.protobuf.CodedOutputStream.computeInt32Size(4, naturalSampleRateHertz_);
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -391,7 +319,7 @@ public boolean equals(final java.lang.Object obj) {
     if (!getName().equals(other.getName())) return false;
     if (ssmlGender_ != other.ssmlGender_) return false;
     if (getNaturalSampleRateHertz() != other.getNaturalSampleRateHertz()) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -412,7 +340,7 @@ public int hashCode() {
     hash = (53 * hash) + ssmlGender_;
     hash = (37 * hash) + NATURAL_SAMPLE_RATE_HERTZ_FIELD_NUMBER;
     hash = (53 * hash) + getNaturalSampleRateHertz();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -541,17 +469,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.Voice.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -670,7 +591,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.Voice other) {
       if (other.getNaturalSampleRateHertz() != 0) {
         setNaturalSampleRateHertz(other.getNaturalSampleRateHertz());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -685,17 +606,56 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.Voice parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                java.lang.String s = input.readStringRequireUtf8();
+                ensureLanguageCodesIsMutable();
+                languageCodes_.add(s);
+                break;
+              } // case 10
+            case 18:
+              {
+                name_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 18
+            case 24:
+              {
+                ssmlGender_ = input.readEnum();
+
+                break;
+              } // case 24
+            case 32:
+              {
+                naturalSampleRateHertz_ = input.readInt32();
+
+                break;
+              } // case 32
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage = (com.google.cloud.texttospeech.v1beta1.Voice) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1170,7 +1130,18 @@ public Voice parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new Voice(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/VoiceSelectionParams.java b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/VoiceSelectionParams.java
index f699dec1..17f0c905 100644
--- a/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/VoiceSelectionParams.java
+++ b/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/VoiceSelectionParams.java
@@ -54,83 +54,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private VoiceSelectionParams(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              languageCode_ = s;
-              break;
-            }
-          case 18:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              name_ = s;
-              break;
-            }
-          case 24:
-            {
-              int rawValue = input.readEnum();
-
-              ssmlGender_ = rawValue;
-              break;
-            }
-          case 34:
-            {
-              com.google.cloud.texttospeech.v1beta1.CustomVoiceParams.Builder subBuilder = null;
-              if (customVoice_ != null) {
-                subBuilder = customVoice_.toBuilder();
-              }
-              customVoice_ =
-                  input.readMessage(
-                      com.google.cloud.texttospeech.v1beta1.CustomVoiceParams.parser(),
-                      extensionRegistry);
-              if (subBuilder != null) {
-                subBuilder.mergeFrom(customVoice_);
-                customVoice_ = subBuilder.buildPartial();
-              }
-
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.texttospeech.v1beta1.TextToSpeechProto
         .internal_static_google_cloud_texttospeech_v1beta1_VoiceSelectionParams_descriptor;
@@ -395,7 +318,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (customVoice_ != null) {
       output.writeMessage(4, getCustomVoice());
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -418,7 +341,7 @@ public int getSerializedSize() {
     if (customVoice_ != null) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(4, getCustomVoice());
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -441,7 +364,7 @@ public boolean equals(final java.lang.Object obj) {
     if (hasCustomVoice()) {
       if (!getCustomVoice().equals(other.getCustomVoice())) return false;
     }
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -462,7 +385,7 @@ public int hashCode() {
       hash = (37 * hash) + CUSTOM_VOICE_FIELD_NUMBER;
       hash = (53 * hash) + getCustomVoice().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -592,17 +515,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.texttospeech.v1beta1.VoiceSelectionParams.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -719,7 +635,7 @@ public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.VoiceSelectionPar
       if (other.hasCustomVoice()) {
         mergeCustomVoice(other.getCustomVoice());
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -734,18 +650,55 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.texttospeech.v1beta1.VoiceSelectionParams parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                languageCode_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            case 18:
+              {
+                name_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 18
+            case 24:
+              {
+                ssmlGender_ = input.readEnum();
+
+                break;
+              } // case 24
+            case 34:
+              {
+                input.readMessage(getCustomVoiceFieldBuilder().getBuilder(), extensionRegistry);
+
+                break;
+              } // case 34
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.texttospeech.v1beta1.VoiceSelectionParams) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1366,7 +1319,18 @@ public VoiceSelectionParams parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new VoiceSelectionParams(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };