Or on the other hand, if they can't read or write I would imagine that you could point to a picture on the menu and indicate what size you want. Or you could draw your own order.
I had to do that once when I came to a drive in and no one at the fast food place could read my order. I literally had to draw my order and indicate what size I wanted. Sometimes I don't use my speech because people will assume I hear much better than I do once they hear my speech
