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.
“You know, because of the lack of budget, we had to find neighborhoods where time had stopped - kind of stuck in the '50s. And no place had that better than Staten Island.”
“When I was a kid, it was a huge insult to be a geek. Now it's a point of pride in a weird way.”