Say you come to China speaking no Mandarin. You settle into some place where the Mandarin spoken is not exactly pǔtōnghuà (普通话 = standard Mandarin as it’s “supposed” to be spoken). Might be out in the countryside. Might be in a city where the dominant language is, say, Wu rather than Mandarin. Might even be in Beijing if you get deep enough into the hutong.
Inevitably you come across someone who tells you you’re saying things wrong: maybe they tell you “10″ is not sí the way you and the locals pronounce it, but is supposed to be shí; maybe they say “blood” is xiě or xuè rather than xuě as everyone you know says it.
But you are linguistically enlightened.
You have no trouble at all, at that point in the conversation, telling the person to take the fast boat back to the imaginary state of pǔtōnghuà. “What is ‘correct’ in language is the behavior of a particular group,” you say. “This group does A, your group does B. Can’t you see how it just doesn’t matter? Can’t you all just get along?”
But can you do the same in your native tongue? Or do you have a particular way of speaking — a particular dialect — that you automatically adopt if you want to sound unedjikated to your friends? John McWhorter has a great dissection of some words about dialect that politician Harry Reid has come to regret, characterizing then-presidential candidate Obama as a man “with no Negro dialect unless he wanted to have one“.
McWhorter’s comments about deeply held dialect prejudice are worth considering next time you use your Mandarin-based linguistic enlightenment to look down on those native speakers who frown on “hick” accents or “improper” Mandarin (native speakers who are often, ironically, speakers of said hick dialects). The prejudices run deeper when you’re born into them.