I say let the market dictate this decision. If he loses business because of his choice in patronage, then so be it. I'm not trying to sound like some sort of internationalist hippy, I just think certain situation would dictate that he needs to accommodate someone who doesn't speak English or as was pointed out earlier, mute. If someone comes here on vacation we should do our best to make them feel at home, we don't want to be like the Parisians!!
I would have less of a problem if before the person could order, they have to show their ID or proof that they were in the legally. Its his business and there's no reason for him to have to run it the way others think he should run it. Freedom fries anyone?