I'm not Southern, but my SIL has picked up a few of those sayings from living in Texas.

Still, I was stunned when I went to church in North Carolina and heard someone stand up and thank "All Y'all." I mean, everyone knows "y'all", but I'd never heard the plural!

Well, except my nephew. He moved to Texas and got invited to a gathering. He was standing right there when they said, "So we'll meet at y'alls house at 7:30."

Someone picked him up, then later found my nephew in the kitchen looking for the nice Y'all family to thank them for their hospitality! True story!