Ain't It the Truth?

[deckardcanine]

There’s a word that I’ve known since my one-digit years,
Yet it still bears a red-squiggle taint.
Grammarians simply don’t want to acknowledge
Legitimate usage of “ain’t.”
I know it’s informal; so what, as the same
Can be said of a bunch of contractions?
Its earliest instance in writing appeared
Before “haven’t,” so why the reactions?
Perhaps they resent it for versatile usage,
As standing for multiple verbs.
If anything, that ought to work as a plus
For the people it somehow disturbs.
Might I also point out that no other good word
Contracts “am not” (no, “aren’t” shouldn’t do).
Lexicographers, programmers, teachers, etc.,
Please allow “ain’t” to go through.