> if someone who didn't hear you says, "what", or "can you say that again?", don't just repeat the last three words you said.

My pet peeve about asking people to repeat isn't that they won't repeat enough, but that they'll repeat in exact the same volume and enunciation as they originally spoke. I'm not sure why they expect to do the same thing again and get different results. The only thing that I've found that works is to tell them what it sounds like they said, no matter how crazy ("Did you say, 'the elephant is painting the room'?") and only then will they speak loud and clear. (Which I'm sure is annoying for the other person, but what else am I to do?)