Thanks man, I'll try it and let you know how it goesI see.
This is what we did to change the in-game Language:
There's a Gear Icon on the left tab. Simply select the option with the speaker in it. You can change to your preferred language by going to the bottom most item.
After successfully changing the Language, I just let the game sit for a few seconds, go back to the song list, then press the Home button and close the game.
No in-game issues since we finished the Project last week.