I came across a blog entry on Language Log discussing change in grammar which I thought I'd point out here.
It basically asks the question, why are we willing to accept words borrowed from other languages but not the fact that grammar changes? It then points out a couple of changes in grammar along the way from Old English to Middle English that we now take for granted but that must have sounded as bad to a speaker of Old English as "Him and me went to the party" does to a modern prescriptivist.
One thing that especially caught my eye was
That grand old idea: there is some logically "correct" English that for some reason most people can't quite pull off, like they don't floss enough. That reminded me of how dialects are sometimes described; they are often treated as people trying to speak the standard language but failing somehow, rather than as people speaking an equally valid variety, which merits study in its own right.
So… at any rate, it made me re-think my stance on prescriptivism.
And rest assured, John McWhorter (the author of the entry) isn't calling for an "anything goes, everywhere" policy; I end with his final paragraph:
Sure, we need a standard language. Every new thing that people start saying cannot be immediately ushered into the house style of the New York Times. But even if it were, it would not spell the death of civilization. More to the point, the novelties in casual speech are just different, not wrong. After all, the grammar I am writing in seems "proper" enough, doesn't it? And yet to the authors of Beowulf, that last sentence would sound like "good" English mangled by a Celt!