dash of racism at the end there, the full package

He is making fun of AAVE, which means African American Vernacular English. Many black people in the U.S. have developed their own cultural accent/way of speaking, it is literally a dialect now, and he is mocking that dialect. It is the same sort of mocking that racists use when they say "dindu nuffin" which is making fun of black people expressing how their fellow brothers and sisters often get killed by police even though "they didn't do anything" or "didn't do nothing".