[jameshart]

British English idioms are often contractions of MUCH longer phrases.

"Y'alrite?" is not, contrary to what you might assume, short for "Are you alright?"

It's short for "Are you alright if I come in and interrupt you? It's fine if you're not, I just wanted to check before barging in. It's really not too much trouble is it? I'll go away and come back later. Or never. Sorry. Sorry, sorry."

[tasuki]

Ah, I'd always thought the "you alright" was passively-aggressively suggesting I was somehow not alright.