Add ContentLanguage to header collection of GetObjectResponse.

generator/.DevConfigs/c49077d9-90b3-437f-b316-6d8d8833ae72.json

@@ -0,0 +1,11 @@
+{
+  "services": [
+    {
+      "serviceName": "S3",
+      "type": "patch",
+      "changeLogMessages": [
+        "Add ContentLanguage to header collection of GetObjectResponse."
+      ]
+    }
+  ]
+}

sdk/src/Services/S3/Custom/Model/Internal/MarshallTransformations/GetObjectResponseUnmarshaller.cs

@@ -87,6 +87,7 @@ private static void UnmarshallResult(XmlUnmarshallerContext context,GetObjectRes
                 response.Headers.ContentEncoding = S3Transforms.ToString(responseData.GetHeaderValue("Content-Encoding"));
             if (responseData.IsHeaderPresent("Content-Language"))
                 response.ContentLanguage = S3Transforms.ToString(responseData.GetHeaderValue("Content-Language"));
+                response.Headers.ContentLanguage = S3Transforms.ToString(responseData.GetHeaderValue("Content-Language"));
             if (responseData.IsHeaderPresent("Content-Length"))
                 response.Headers.ContentLength = long.Parse(responseData.GetHeaderValue("Content-Length"), CultureInfo.InvariantCulture);
             if (responseData.IsHeaderPresent("x-amz-object-lock-legal-hold"))

sdk/test/Services/S3/IntegrationTests/GetObjectTests.cs

@@ -246,5 +246,50 @@ public void TestContentLanguageResponseHeaderOverride()
                     "Original ContentLanguage should still be stored when no override is specified");
             }
         }
+
+        [TestMethod]
+        [TestCategory("S3")]
+        public void TestContentLanguageHeadersCollection()
+        {
+            var key = "TestContentLanguageHeadersCollection";
+            var expectedLanguage = "de-DE";
+
+            // Put object with Content-Language header
+            var putRequest = new PutObjectRequest
+            {
+                BucketName = bucketName,
+                Key = key,
+                ContentBody = "Test content for Content-Language headers collection"
+            };
+            putRequest.Headers["Content-Language"] = expectedLanguage;
+
+            Client.PutObject(putRequest);
+
+            // Get object and verify both ContentLanguage properties are set
+            var response = Client.GetObject(new GetObjectRequest
+            {
+                BucketName = bucketName,
+                Key = key
+            });
+
+            using (response)
+            {
+                // Verify the direct ContentLanguage property
+                Assert.IsNotNull(response.ContentLanguage, 
+                    "ContentLanguage property should not be null");
+                Assert.AreEqual(expectedLanguage, response.ContentLanguage,
+                    "ContentLanguage property should match the value set during PutObject");
+
+                // Verify the Headers.ContentLanguage property
+                Assert.IsNotNull(response.Headers.ContentLanguage, 
+                    "Headers.ContentLanguage property should not be null");
+                Assert.AreEqual(expectedLanguage, response.Headers.ContentLanguage,
+                    "Headers.ContentLanguage property should match the value set during PutObject");
+
+                // Verify both properties have the same value
+                Assert.AreEqual(response.ContentLanguage, response.Headers.ContentLanguage,
+                    "ContentLanguage and Headers.ContentLanguage should have the same value");
+            }
+        }
     }
 }