By the use of those examples, Bill Cosby added energy to the ghetto talkin Black folks stereotype.
I wonder-which audience was he speaking to when he mouthed those words? Hmmm.
Though there's no question that in order to "make it" in mainstream American society, people need to know how to speak & write what is generally considered to be standard English, there are other standards, and other languaging modalities in this country. Included among them are many creative African American oral and written traditions old and new- such as jazz jive talk and hip-hop. These creative soul traditions help to keep the English language fresh.
So later for Bill Cosby. As the young girls say in their street cheers: "Poof with the attitude"! And as some of those hanging on street corner guys might say---well-I won't go there. But just use your imagination. It's a free world-or so they say.