Can you believe it? I almost fell over. I'm surprised I sound so unsurprised on the video. He did the same thing for cracker (which at the moment is his most favorite food - Ritz crackers, specifically). He knows I keep them behind where he's sitting in the video, and when I said it, he completely turned around and pointed. How exciting!
Here's another video that shows two different things. First, how he "dances" when he hears music (he does it much better than that, but it at least illustrates the point), and how he "signs" uh-oh. I don't know if it's REALLY how you sign uh-oh, but that's at least his *home sign* for it. It was suggested by his speech therapist (who signs also, incidentally). I think she's amazing, by the way.
So, the turn taking we've been practicing for the past year paid off today. I waited for a response, and I got one. I need to learn to be more patient more often.