public Builder mergeFrom(com.google.cloud.texttospeech.v1beta1.ListVoicesRequest other) {
      if (other == com.google.cloud.texttospeech.v1beta1.ListVoicesRequest.getDefaultInstance())
        return this;
      if (!other.getLanguageCode().isEmpty()) {
        languageCode_ = other.languageCode_;
        bitField0_ |= 0x00000001;
        onChanged();
      }
      this.mergeUnknownFields(other.getUnknownFields());
      onChanged();
      return this;
    }
<pre>
The top-level message sent by the client for the `ListVoices` method.
</pre>

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