When you don't quite hear what someone has said is it more proper to say 'sorry' or 'pardon me'?

Answer 1

Sounds more like an etiquette question than a grammar question, actually. There are no grammatical rules about which to say. (From a usage standpoint you would say "pardon me" rather than "pardon you" however.) From a general communication standpoint it might be more clear to say something like "I'm sorry, would you repeat that?" If you can be specific about how much of the conversation you failed to hear, that would also be helpful.