What or Pardon-Neither!!!!

Silly question, isn't it? Obviously it depends on whom you are talking to. If a complete stranger asks me a question I haven't properly heard or understood, I'd say 'pardon' or 'I beg your pardon'. If it's one of the family I'd usually say 'what?'

"What?" Is correct. It's short for "I'm sorry, what did you say?"

Or so I was taught by a fantastically knowledgeable headmistress, sixty years ago.

I use all sorts of phrases when I don't hear what someone said: "Say again?" "I didn't hear that", "I couldn't hear what you said; you're muttering again", "comó?" or, of I'm feeling particularly Lancastrian "Yer what, luv?"

An enquiring tilt of the head works too.

It's a tricky one. I agree that 'pardon' is wrong, but because it's the word that is in majority use, teaching your child to say 'excuse me I didn't hear' or 'what did you say' may set them apart from their peers. With the incidence of bullying such an issue in schools, the last thing anyone would wish to do is bring their child up to be 'different' in any way.

Also, either of the alternatives are likely to be shortened: 'excuse me', to my mind, is the equivalent of 'pardon', i.e. apologising for some minor wrongdoing, and 'what' does sound rather blunt (although I've always understood that this is the expression favoured by the upper classes ).

I really don't care - isn't this all some kind of snobbery?

So long as i understand that someone is asking me to repeat something they didn't hear or understand then that's fine by me.

Agree with trisher and merlotgran.

I was taught to say, 'What did you say?' as 'What?' sounded abrupt and rude and should only be used as an expression of disbelief, as in, 'Yer What?'

Nowadays people tend to say, 'Sorry?' if they don't hear you the first time or if on the phone, 'Say again?' which I find irritating.