*Sigh* "Ain't" is understandable. Nobody denies that. What the seventy thousand users above (who you seem to want to argue with) are telling you is it's NOT acceptable, normal english. It is, at best slang. English teachers around the globe would slap you with their rulers for using it. That was the only point! And, a word of advice for the future: saying "well, Eminem said it." is NEVER a good excuse. That's like saying all Russians must own performing bears, since you saw it in a movie!