protected void listAllVoices() {
        System.out.println("--------------------------------------------------");
        System.out.println("All voices available:");
        VoiceManager voiceManager = VoiceManager.getInstance();
        Voice[] voices = voiceManager.getVoices();

        for (Voice voice : voices) {
            System.out.printf(" - [%s] %s\n", voice.getDomain(), voice.getName());
            System.out.printf("   Description : %s\n", voice.getDescription());
            System.out.printf("   Age         : %s\n", voice.getAge());
            System.out.printf("   Gender      : %s\n", voice.getGender());
            System.out.printf("   Locale      : %s\n", voice.getLocale());
        }
        System.out.println("--------------------------------------------------");
        System.out.println();
    }