diff --git a/api/SpeechRecognition.json b/api/SpeechRecognition.json
index 7c3dca5cba9ed..d4b8d1913c045 100644
--- a/api/SpeechRecognition.json
+++ b/api/SpeechRecognition.json
@@ -1183,6 +1183,536 @@
             "deprecated": false
           }
         }
+      },
+      "events": {
+        "audioend": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/audioend_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "audiostart": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/audiostart_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "end": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/end_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "error": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/error_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "nomatch": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/nomatch_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "result": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/result_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "soundend": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/soundend_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "soundstart": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/soundstart_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "speechend": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/speechend_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "speechstart": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/speechstart_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "start": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechRecognition/start_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": true
+              },
+              "edge": {
+                "version_added": false
+              },
+              "edge_mobile": {
+                "version_added": false
+              },
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": {
+                "version_added": false
+              },
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": false
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": {
+                "version_added": false
+              },
+              "webview_android": {
+                "version_added": true
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        }
       }
     }
   }
diff --git a/api/SpeechSynthesis.json b/api/SpeechSynthesis.json
index 3abcc96231da1..9beb8cbd2adaa 100644
--- a/api/SpeechSynthesis.json
+++ b/api/SpeechSynthesis.json
@@ -608,6 +608,69 @@
             "deprecated": false
           }
         }
+      },
+      "events": {
+        "voiceschanged": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechSynthesis/voiceschanged_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": "33"
+              },
+              "edge": {
+                "version_added": "14"
+              },
+              "edge_mobile": {
+                "version_added": true
+              },
+              "firefox": {
+                "version_added": "49"
+              },
+              "firefox_android": [
+                {
+                  "version_added": "62"
+                },
+                {
+                  "version_added": "61",
+                  "version_removed": "62",
+                  "flags": [
+                    {
+                      "type": "preference",
+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
+                    }
+                  ]
+                }
+              ],
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": "21"
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": "7.1"
+              },
+              "webview_android": {
+                "version_added": "4.4.3"
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        }
       }
     }
   }
diff --git a/api/SpeechSynthesisUtterance.json b/api/SpeechSynthesisUtterance.json
index 2fcf7d37ff2ab..5fa828933434c 100644
--- a/api/SpeechSynthesisUtterance.json
+++ b/api/SpeechSynthesisUtterance.json
@@ -914,6 +914,435 @@
             "deprecated": false
           }
         }
+      },
+      "events": {
+        "boundary": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechSynthesisUtterance/boundary_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": "33"
+              },
+              "edge": {
+                "version_added": "14"
+              },
+              "edge_mobile": {
+                "version_added": true
+              },
+              "firefox": {
+                "version_added": "49"
+              },
+              "firefox_android": [
+                {
+                  "version_added": "62"
+                },
+                {
+                  "version_added": "61",
+                  "version_removed": "62",
+                  "flags": [
+                    {
+                      "type": "preference",
+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
+                    }
+                  ]
+                }
+              ],
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": "21"
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": "7.1"
+              },
+              "webview_android": {
+                "version_added": false
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "end": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechSynthesisUtterance/end_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": "33"
+              },
+              "edge": {
+                "version_added": "14"
+              },
+              "edge_mobile": {
+                "version_added": true
+              },
+              "firefox": {
+                "version_added": "49"
+              },
+              "firefox_android": [
+                {
+                  "version_added": "62"
+                },
+                {
+                  "version_added": "61",
+                  "version_removed": "62",
+                  "flags": [
+                    {
+                      "type": "preference",
+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
+                    }
+                  ]
+                }
+              ],
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": "21"
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": "7.1"
+              },
+              "webview_android": {
+                "version_added": false
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "error": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechSynthesisUtterance/error_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": "33"
+              },
+              "edge": {
+                "version_added": "14"
+              },
+              "edge_mobile": {
+                "version_added": true
+              },
+              "firefox": {
+                "version_added": "49"
+              },
+              "firefox_android": [
+                {
+                  "version_added": "62"
+                },
+                {
+                  "version_added": "61",
+                  "version_removed": "62",
+                  "flags": [
+                    {
+                      "type": "preference",
+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
+                    }
+                  ]
+                }
+              ],
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": "21"
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": "7.1"
+              },
+              "webview_android": {
+                "version_added": false
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "mark": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechSynthesisUtterance/mark_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": "33"
+              },
+              "edge": {
+                "version_added": "14"
+              },
+              "edge_mobile": {
+                "version_added": true
+              },
+              "firefox": {
+                "version_added": "49"
+              },
+              "firefox_android": [
+                {
+                  "version_added": "62"
+                },
+                {
+                  "version_added": "61",
+                  "version_removed": "62",
+                  "flags": [
+                    {
+                      "type": "preference",
+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
+                    }
+                  ]
+                }
+              ],
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": "21"
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": "7.1"
+              },
+              "webview_android": {
+                "version_added": false
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
+        "pause": {
+          "__compat": {
+            "mdn_url": "https://developer.mozilla.org/docs/Web/API/SpeechSynthesisUtterance/pause_event",
+            "support": {
+              "chrome": {
+                "version_added": "33"
+              },
+              "chrome_android": {
+                "version_added": "33"
+              },
+              "edge": {
+                "version_added": "14"
+              },
+              "edge_mobile": {
+                "version_added": true
+              },
+              "firefox": {
+                "version_added": "49"
+              },
+              "firefox_android": [
+                {
+                  "version_added": "62"
+                },
+                {
+                  "version_added": "61",
+                  "version_removed": "62",
+                  "flags": [
+                    {
+                      "type": "preference",
+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
+                    }
+                  ]
+                }
+              ],
+              "ie": {
+                "version_added": false
+              },
+              "opera": {
+                "version_added": "21"
+              },
+              "opera_android": {
+                "version_added": false
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": "7.1"
+              },
+              "webview_android": {
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+                      "name": "media.webspeech.synth.enabled",
+                      "value_to_set": "true"
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+              "deprecated": false
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+              "standard_track": true,
+              "deprecated": false
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+          }
+        }
       }
     }
   }