A few years ago when I started having kids, my wife and I were friends with a couple whose parents were each second generation American Chinese. The mother's p

A few years ago when I started having kids, my wife and I were friends with a couple whose parents were each second generation American Chinese. The mother's parents' native language was Cantonese, the father's was Mandarin. They wanted their kids to learn their familes' languages, so the mother would speak Cantonese to the children, the father would speak Mandarin, and they figured the kids would pick up English from everyone else. Once their oldest son came up to me and asked for something in (I think) Mandarin. I told him in English, "I can't understand you, what do you want?" and I could almost see the wheels turning inside his head: oh, this guy doesn't know Mandarin, better try Cantonese. So he said something in Cantonese and I said the same thing in English and I think I blew his mind. His eyes got really big and he kind of backed away from me, the way kids do when something's scary and fascinating at the same time, and ran to get his mom. He speaks perfect English now, so I guess it all worked out.