Let him say what he wants to say, my wife sometimes helps me with a word if i have a real bad block but she never cuts me off and starts talking about something else because I have a pause. To me, when i get stuck on a word and someone changes the subject or doesnt let me finish I feel like less of a human and humiliated. If you go somewhere where he has to place an order it can be sometimes hard to talk when your on the spot so you can ask him if you want to say his order for him.