Americans (I'm one) seem to have an incessant need to shorten words and phrases to the minimum required to get the point across. I'm not sure if this is related to the incessant
speeding-up of our culture, sheer laziness, or just ornery anti-
Englishism.
Automobile becomes
autocar becomes
auto becomes
car.
Macintosh computer becomes
Mac immediately. An Intel-based PC running Windows becomes a
Wintel Box.
Aeroplane? Nope.
Airplane? Sometimes.
Plane, usually. Entire phrases aren't safe.
Is that okay? becomes
OK? This is in contrast to other cultures' slang (not all of course). Take
Cockney rhyming slang; it typically turns one word into a two-word pair that rhymes with the original word.
In extreme situations, this can hypertrophy into the American Acronymization Reflex (AAR).