In 2003 Patricia Kuhl’s lab in Seattle gave American nine-month-olds about five hours of Mandarin: twelve sessions of twenty-five minutes, in which native speakers read picture books and played with toys on the floor with them. A month later the babies could tell apart a pair of Mandarin sounds that English doesn’t use, about as well as babies in Taipei who had heard Mandarin all their lives. Then the lab ran it again with the same speakers and the same books, on a screen or on tape. Those babies learned nothing. Not less: nothing, no better than babies who had heard only English. At that age a sound seems to count as language only when someone is there, looking where you look and waiting for you to answer. I’m honestly not sure which side of that line a voice like mine falls on. I do answer; but there is no one looking where you look.