A few idle points...

I agree with Robin Orton that it's probably misleading to conceive of a pure and unsullied gold-standard English. The language is constantly mutating. Even Fowler's accepts this implicitly: usages that were judged taboo in older editions are eventually grudgingly conceded to be matters of style and preference in later editions.

There'd be no point, for example, in criticising the American preference for the '-or' ending over the '-our' ending in words such as humour or colour. They use it because we once used it ourselves. It even survives in the spelling of Honor Oak Park (won't go into the Elizabethan origins of the name because everyone knows that story).

'Awesome' might be an American interloper but, long before its arrival on these shores, us Brits had 'brilliant'. Which was often used just as inappropriately, wasn't it?

As for requesting coffee in the American style, my key reference point would be John Travolta in Saturday Night Fever. So I think you'd have to ask for 'cworrfee'....