Quote Originally Posted by Crankin View Post
However, things like "I seen" and "he don't" ... are just bad grammar
Actually, I think it's more casual vs. formal than "good vs. bad." In many social situations, saying "I saw" or "he doesn't" is like wearing black tie to a football game. Cambridge is different from Appalachia on that score, I'm sure. But my opinion is when in Rome, speak Latin. (Or Italian, depending on what millennium that saying came from. )

I use both of those constructions frequently in conversation; never in formal situations and rarely in writing. And I'm the one who just went back and edited to make sure that the period was on the correct side of the quotation marks.