private void ensureLanguageCodesIsMutable() {
      if (!languageCodes_.isModifiable()) {
        languageCodes_ = new com.google.protobuf.LazyStringArrayList(languageCodes_);
      }
      bitField0_ |= 0x00000001;
    }
<pre>
Description of a voice supported by the TTS service.
</pre>

Protobuf type {@code google.cloud.texttospeech.v1beta1.Voice}
java-texttospeech/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/Voice.java