@java.lang.Override
  public com.google.protobuf.ByteString getSourceLanguageCodeBytes() {
    java.lang.Object ref = sourceLanguageCode_;
    if (ref instanceof java.lang.String) {
      com.google.protobuf.ByteString b =
          com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
      sourceLanguageCode_ = b;
      return b;
    } else {
      return (com.google.protobuf.ByteString) ref;
    }
  }
<pre>
Required. The BCP-47 language code of the input document if known, for
example, "en-US" or "sr-Latn". Supported language codes are listed in
[Language Support](https://cloud.google.com/translate/docs/languages).
</pre>

<code>string source_language_code = 2 [(.google.api.field_behavior) = REQUIRED];</code>

@return The bytes for sourceLanguageCode.
java-translate/proto-google-cloud-translate-v3beta1/src/main/java/com/google/cloud/translate/v3beta1/BatchTranslateDocumentRequest.java