public Builder mergeAdvancedVoiceOptions(
        com.google.cloud.texttospeech.v1.AdvancedVoiceOptions value) {
      if (advancedVoiceOptionsBuilder_ == null) {
        if (((bitField0_ & 0x00000008) != 0)
            && advancedVoiceOptions_ != null
            && advancedVoiceOptions_
                != com.google.cloud.texttospeech.v1.AdvancedVoiceOptions.getDefaultInstance()) {
          getAdvancedVoiceOptionsBuilder().mergeFrom(value);
        } else {
          advancedVoiceOptions_ = value;
        }
      } else {
        advancedVoiceOptionsBuilder_.mergeFrom(value);
      }
      if (advancedVoiceOptions_ != null) {
        bitField0_ |= 0x00000008;
        onChanged();
      }
      return this;
    }
<pre>
Advanced voice options.
</pre>

<code>optional .google.cloud.texttospeech.v1.AdvancedVoiceOptions advanced_voice_options = 8;
</code>
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechRequest.java