It just seems like when someone start learning and getting intelligent or start feeling intelligent they act as if when you say slang they do not understand, but they understood before i know grammar is very important to some people but for an example someone say " thang " instead of "thing" certain people will seem to not know and say "what is a thang"?
Honestly i think many people know but they question it like they do not know or comprehend but in reality they do know
First of all, the words you choose to pull out of your vocabulary make no difference on how intelligent and unintelligent you, some people just enjoy the luxury of slang. Second of all, if you once spoke slang, chances are you'll remember it, the only difference is, you choose to use proper English
From my high school I suppose. McDonald's cashier is the most gangsta job imaginable, and I don't mean that in a good way, at all. Many of them said things like, "Yo, B, what up." Or, "I'm not playin, pay for your mothaf--king Big mac."
But then again there's cool slang like "bro" and "bud" and dumb slang like the n-word, ghettoized.