That's right, it's y'all. Oh, I still say 'you guys' once in a while, or even 'youse guys' if I'm in the right mood. It comes from living in a lot of different places, and they all say things in a lot of different ways.
Look at this page if you want to see how usage of various expressions varies geographically in the US. Here's an example:
64. What do you call the long sandwich that contains cold cuts, lettuce, and so on?I guess they've never been to Florida, or else somebody would have said a Cuban sandwich. And I'm surprised Dagwood isn't on there somewhere. Anyway, I suppose it's a half-decent way to get an idea where someone comes from.
a. sub (77.15%)
b. grinder (2.87%)
c. hoagie (6.98%)
d. hero (5.18%)
e. poor boy (1.77%)
f. bomber (0.01%)
g. Italian sandwich (0.46%)
h. baguette (0.25%)
i. sarney (0.03%)
j. I have no word for this (0.91%)
k. other (4.41%)
They left off some good ones though. I thought surely "y'all" would be on there, but I missed it if it was. They were probably too PC to include ethnicity, and too chicken to include anatomical features (some of my favorites are for "perineum").
Stolen from Eric Mulkowsky (must be a Polack or a bohunk) of Max Power.