y'all IS plural. It refers to a group of people. Any other usage (as in a Yankee gal on TV using a pretend Southern accent to say "you all" when referring to one person) is silly and not real.
The way I hear it spoken here, Y'all is singular or plural.
"All y'all" is always plural.
"y'all" is collective. "all y'all" is plural.
The plural of y'all is.....
all y'all. ;o)
My friend, the Belle of Red Stick down in Louisiana, says that Y'all in singular, and "All Y'all" is plural". :-)
Although I have lived up North most of my life, my mother's a tarheel, so I know something about this one. What this expresses is not just ignorance on the part of the Yankee but lack of manners as well. You walk into the hardware store by yourself and the man behind the counter (whom your family has known for 30 years) greets you and says, "How y'all do'in?"
Any ignorant rude uncouth Yankee immediately thinks the man has committed a grammatical error because the self-centered Yankee thinking like Hillary that everything is about him thinks that the man behind the counter is only asking about the damned Yankee himself. What is not recognized by said ill-bread uncouth Yankee is that the gentleman behind the counter is politely asking about the whole family whose comings and goings he has followed for 30 years. Dumb ill-mannered uncouth self-centered Yankees should stop expressing opinions about things they don't know anything about - but when did that ever stop a liberal.
You are so, so right on that one!
BTW, when I was in seminary - in N'awlins, no less - in my Hebrew classes, I always, always translated the "second person plural" as "y'all."
My professor didn't like it very much, but what could he do? After all, it was grammatically correct!