public UnaryCallSettings<ListVoicesRequest, ListVoicesResponse> listVoicesSettings() {
    return ((TextToSpeechStubSettings) getStubSettings()).listVoicesSettings();
  }
Returns the object with the settings used for calls to listVoices.
java-texttospeech/google-cloud-texttospeech/src/main/java/com/google/cloud/texttospeech/v1beta1/TextToSpeechSettings.java