This post ain't going to take long to read. Ain't might not have become more standardized in workplace writing, but it is becoming more common in speech. And you can bet that standardized speech eventually becomes standardized workplace writing. You can do your own research on this fact.
You'll never get an opponent to concede that ain't is Standard English, but you will win this one: Ain't has a long history of standard usage before it was discredited by prescriptive grammarians, and I completely understand why. We have standard contractions for you, we, and they are not (aren't) and he, she, and it is not (isn't). But we don't have one for I am not, although amn't has a history of standard English usage. Thus, we have ain't.
Since ain't has not disappeared from English for over three centuries, I believe it will become standard in both speech and writing. Ain't is gaining momentum.
