a PHD in hip hop?

the first three entries for "language" on dictionary.com:

1. a body of words and the systems for their use common to a people who are of the same community or nation, the same geographical area, or the same cultural tradition: the two languages of Belgium; a Bantu language; the French language; the Yiddish language.
2. communication by voice in the distinctively human manner, using arbitrary sounds in conventional ways with conventional meanings; speech.
3. the system of linguistic signs or symbols considered in the abstract (opposed to speech).
 
the first three entries for "language" on dictionary.com:

1. a body of words and the systems for their use common to a people who are of the same community or nation, the same geographical area, or the same cultural tradition: the two languages of Belgium; a Bantu language; the French language; the Yiddish language.

This is the only one that could fit ebonics.

Now the question is whether it is sufficiently different from English to justify classification as its own language. Given that it is entirely based on English, I'd have to say no. The comparison with 1337 seems entirely legitimate to me.