Faster variant of "are you"? Most of the time, (but not always) spoken at the end of a sentence, comment, challenge, statement, or unsult...Basically, the word breaks down to:
izzya==is ya==is you==are you...The words "are" and "is" have identical meanings around here(?)
Izzya ready to go to school, Jimmie?
You lookin' at me kinda funny, Petey...You ain't aimin' ta toss my salad, izzya?