My wife spent about half a year in North Carolina for work, where "y'all" seemed to translate to the singular "you", while "all y'alls" was used to refer to "you" plural.

I have used y'all for as long as I can remember (although not exclusively...it is mixed in with "you guys", "you people", and others according to whichever sounds best in that particular sentence), even though the farthest I was ever away from the West Coast for my first 47 years was just outside Yosemite in California, and I knew nobody who was from the South or spoke with any obvious Southern influence.

I think I must have heard it on TV and picked it up.

Anyone else here use it despite no Southern connection among friends or family?

One of my foreign friends was teasing me about how English doesn't have a word for "a group of people" whereas many other major languages apparently do, and I replied "sure we do, it's y'all".