The idea that commercial speech is "White" is really just a post hoc ergo propter hoc fallacy. Ask any Cockney if they speak “White” in The City. No, they speak Commercial English, which is largely standard English, or, over there, the Queen’s English. It just so happens that commerce is dominated by White people, and some White kids prepare for commercial life by learning to speak that language, because it’s spoken at home by people in, wait for it, COMMERCE. Meanwhile, it’s a foreign tongue to your cabbie, innit?