> If grammar rules should reflect usage, can anything somebody uses be wrong?

If I want to present a similar false dichotomy, I'd say if grammar doesn't reflect usage, it can never change.

Obviously there's a middle ground. "Reflect usage" is not the same as "everything anyone says is correct." As uses that were once ungrammatical become more and more common, the rules of grammar change. The rules change as new ones are accepted by more and more people. Language evolution is a weird and complex process that doesn't have a whole lot of rhyme or reason to it.

Language is best looked at not as being some fixed set of rules and words that come down from on high but as a more fluid set of rules and words that is generally agreed on by the native-speaking population. Grammar thus should reflect common usage, not every single slip-up a speaker makes.

If grammar doesn't reflect usage, what the heck does it reflect? There's nothing else to go by. Even when people arbitrarily made up rules for English grammar (e.g. no split infinitives), they were going by usage in another language.

Stephen