People who correct others’ grammar seem to assume that grammatical rules were handed down on high from some kind of unimpeachable entity, and that anyone who doesn’t talk right simply hasn’t been shown the light. But the opposite is true: Humanity developed language as a community effort, then some people noticed patterns and wrote them down. But the rules were slightly different everywhere, so eventually, one ruling class decided to use it as an excuse to punish poor people who say “y'all” or live in the inner city.
“But there have to be rules,” says the Snob, “or language devolves into chaos.” Only there are rules. Every dialect ever, from the nasally Midwestern to the slow Southern drawl to Valley Girl gibberish to the Mark Whalbergian shrieks of Boston, has its own strictly followed rules, even if the speakers don’t know they follow them. You follow hundreds of “rules” without realizing them, because instead of being taught them by a stern teacher, you just heard it as a baby and internalized it without ever saying it out loud.