[mtviewdave]

>So should there be AAVE-English academic dictionaries with entries like "ain't: are not", etc.?

This is already the case in Standard English dictionaries: http://www.merriam-webster.com/dictionary/aint

>What about l33tsp34k and txtng spk, u wnt 2gt dctnrz 4 it 2?

Actually, given how often I see it, I wouldn't be surprised if "U" was the standard English spelling for the second-person pronoun (or at least an acceptable variant), by the end of this century. It wouldn't be the first time an English pronoun's spelling collapsed down to a single letter ("I" was originally "Ic").

[Evbn]

U is logically parallel to I, and is accepted in (India) Indian English.