@IndianaJoe3 I'm trying to model it because they can't understand him if they can't see him. In essence, what i'm trying to give him is Speech, Invisible to Hearing Group, but Obvious to Sight Group. I just don't know how to do that. I like the language skill idea, but then others would need to take the language as well. Skills can be built as powers though. Is Language: Tactical Hand Signals, Usable on Other legal?
@LoneWolf It is a mystical ability. He's using his ki to project his current intentions to those that can perceive him (whether he's aware of them or not, so anyone eavesdropping on the conversation would "hear" what the ninja is saying, provided they see the him). It's an ability that is intrinsic to his ninja training.