People do this to the handicapped, the blind, etc. etc. It's stupid as hell, and often very frightening if you are on the receiving end.

Flip side of the coin: People who speak very loudly in their native tongue when they are in a foreign country. They needn't even be tourists, they can be immigrants or other visitors as well. I can't tell you how many times I've been sitting on a bus and heard a pair of people talking at the top of their lungs about something of a very personal nature.

Chinese people, that is, speaking Mandarin in San Francisco. I'm American...not deaf. And despite all the jokes you hear (semi-true though they are), SOME Americans speak more than one language! GASP!