In British English we distinguish between (for example):
'Did you see the film?'
'Have you seen the film?'
They both imply slightly different things.
Furthermore, I would never say, 'Did you see the film yet?' while I would say, 'Have you seen the film yet?'
What are the names of these two different tenses?
Is my observation that Americans only use the 'did' form and not the 'have' form true?
Can speakers of American English comprehend the different nuance of each form?
What do speakers of other dialects of English use in these situations?
And finally, I'm trying to explain to myself what this difference is, clearly, but it's not easy to do! Can someone help me out?
EDIT: Just for emphasis: the most striking example was when one person asked a friend, "Did you hear of this band?" and she replied, "I did!"
It just sounded so strange to me; I would have said, "Have you heard of this band?" or replied "I have!"
EDIT TWO: Thanks everyone. It seems as though my friends are using one form predominantly in the spoken language, but generally US English does make the same distinction.