Makes Me Wonder

While we were having lunch at McDonald's yesterday (even though we just spent one week around McDonald's food 24/7), we noticed a group of families gathered together, lounging around in the McCafé (as so many do in Germany as the restaurants are designed for comfort). Both the kids and adults were signing to one another. Which made me think, "Do they sign in German?" I suppose the essence of sign language is that the "words" are universal, but they throw in German words where necessary. I wonder what the sign is for "pretzel?"