I think that I've collected enough foreign (or, well, they might as well be) words and phrases to warrant a second edition! Of course, I've probably forgotten to include some now that I am getting used to saying them...
quid - slang for pounds, the currency used in the UK
chuffed - pleased
sultana - Alright, well, we technically do have these in the U.S...they're really just grapes, but they're a special kind of grape. The raisin form of the same name (confusing!) is used in SO MANY dishes here!
Slightly Different Usage
diary - agenda/planner
"Alright?" - "How are you?"
"Is that you?" - "Are you leaving?"
caster sugar - superfine sugar
icing sugar - powdered sugar
"Cheers!"* - "Thanks!"
phone - (v.)