How do I determine when Google maps is Speaking in Android

I'm trying to modify my application to pause audio playback when Google maps is announcing a turn by turn direction.

I've added the following code (shown below) to my application. The audio focus listener is called when applications like Pandora Radio or Spotify request audio focus in order to play music but it's not called when Google maps announces a turn by turn direction. Is there another intent I should be listening for in order to detect this behavior?

 AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    audioManager.requestAudioFocus(new AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
            .setAudioAttributes(
                    new AudioAttributes.Builder()
                            .setUsage(AudioAttributes.USAGE_MEDIA)
                            .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
                            .build()
            )
            .setAcceptsDelayedFocusGain(true)
            .setOnAudioFocusChangeListener(new AudioManager.OnAudioFocusChangeListener() {
                @Override
                public void onAudioFocusChange(int focusChange) {
                    // This is called by Pandora Radio and Spotify
                    Log.d("Focus change:", " Event is: " + focusChange);
                }
            }).build());

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