Is that short for something? …a cartoon reference?..?
It’s just a patronising kind of way of saying “Okay?”
M’kay?
Popularized by the teacher in South Park.
[quote]
Popularized by the teacher in South Park.[/quote}
I thought Mr. Mackey was the school counselor. 
It’s a silly speech affectation people normally use to be overly dramatic.
Actually, that teacher on Beavis and Butt-Head was using it first.
So, is that pronounced um.kay or McKay?