How to (not) make someone who speaks another language understand you

In the U.S. I've often seen people raise their voice, or actually shout, at people who don't speak English. The theory seemed to be that if you talk loud enough the people will understand. It never made sense to me but I've seen it done many times.

A couple of days ago I was on the receiving end. I was in a restaurant, in a city an hour away from Beijing by train, and apparently the family had never had with foreigners in their business before. The owner/cook was a sweet man and ended up making me something special that wasn't on the menu. He seemed to subscribe to the same theory as many others around the world - he raised his voice and started yelling when it became apparent that I didn't understand what he was saying.

I resisted the urge to break out in laughter and instead pulled out my Mandarin notes. He, his wife and son were very interested. The written characters were helpful to use to explain that I'm allergic to meat.

Shouting didn't work. Smiling, laughter, facial expressions and drawings did.