It appears that the present-day form of African American English is not the inheritance of the period of slavery, but the creation of the second half of the 20th century.
“I just found out last week - my sister told me - that my father had some Beatles records. So I must have heard them quite a bit, but it never registered, really. Now I listen to them with new ears.”
“I didn't know folk music growing up, no. It's something I've come to study, really, because I think there's so much to learn from traditional music in the sense of the way music began as a way of communication, the traveling storyteller, the bard, the minstrels.”