Re: AAE doesn't actually exist as "a language".
It doesn't exist as a language because the powers that be have decided it shouldn't be accorded that status. But it is at least as distinct from American English as British English is, so I don't see why it shouldn't be.
They'd rather just consider speakers of AAE as being "illiterate" and unable to speak proper American English, when in fact many are able to switch between American English and AAE as smoothly as some bilinguals can switch between English and French on the fly.