In responce to Zenako:
Actually a mute spell would be somewhat nice. But I dont think it would function quite like your thinking. If it was like in other RPG type games (FF) it would make it so that bards couldn't sing, Casters couldnt cast spoken spells but hand movement ones could be, and maybe diplo, bluff, and intimidate wouldn't work either. But sonic damage from like the von 5 boss stomping would still work.
Just my thoughts.
also I agree that perfom would go against Will saves.
Again just my 2 cp