myTTS.synthesizeToFile(text, null, file, null);

myTTS.setOnUtteranceProgressListener(new UtteranceProgressListener() {
    @Override
    public void onStart(String utteranceId) {
        System.out.println(".......START!!!  ");
    }

    @Override
    public void onDone(String utteranceId) {
        System.out.println("...........OK!!!  ");
    }

    @Override
    public void onError(String utteranceId) {
        Log.e(TAG, "Error while trying to synthesize sample text");
    }
});