Originally Posted by Prestidigitweeze
We all know about the list, Murray Paul -- and thank you, kind sir, for suggesting I sounded like a prim regulator even as I made fun of my own primness [insert schizophrenia emoticon]* -- but that doesn't mean usage alone defines English grammar. Unregulated or otherwise, language is not the model for a libertarian's dream of a regulation-free world. If correct grammar were completely beholden to individual usage, then English teachers, professors, writers, editors and proofreaders wouldn't be needed.
* (I hope it's apparent I'm kidding about a link to a list of regulators implying personal insult.)
Joking aside, usage IS what defines English. Rules are written after the fact. Go read how any of our "standards" are created and you will see that came out of studying how words/etc were used.
Teachers/etc help slow change down, and help teach the current state... but ultimately usage drives the rules, not the other way around.