[hijack]In eighth grade, we were learning those rules. In Spanish, the formal second person often appears identical to the third person: “your” and “his” are both “su,” whereas the informal “your” is “tu.”
Our textbook had a mildly humorous passage to illustrate the difficulty. One character tells a stranger on the beach that “su” towel just got blown away by the wind, and the second character is all, why would I care about what happens to his towel? The first character asks if he can be informal (puedo tutearlo consigo or something like that); the second agrees; he then explains that “tu” towel got blown away, and the second character goes chasing after the towel after Ayayaying it up.
Our genius of a Spanish teacher had us read the passage out loud, round robin, in English. There’s absolutely no way to make the story coherent in English.
Again, I have no idea where this absurd style of thinking comes from. Just because it’s “wrong” to use “y’all” in the singular doesn’t mean it never happens. It happens a lot. And not just in Oklahoma and it has nothing whatsoever to do with non-Southerners. A lot of use hear this on a regular basis. This is called “reality”. Deal with it.
And remember, it’s not just used as a 2nd person pronoun, it’s becoming progressively used as a generic filler word.
Some people like saying it, so they say it in situations where it’s not needed or makes no sense.