The Language Explosion

Barry IS A PIXIE-FACED 3-YEAR-OLD WHO CAN'T yet draw a circle or stack his blocks in a simple pattern. There is little chance he will ever live independently. He may never learn to tie his own shoes. Yet Barry is as chatty and engaging a person as you could ever hope to meet. He knows his preschool classmates-and their parents-by name. When he wakes his mom in the morning, he strokes her cheek and tells her how beautiful she is. Then he asks her how she slept. Barry has Williams syndrome, a rare congenital disorder caused by abnormalities on chromosome 7. Children with the condition share an array of distinctive traits, including weak hearts, elfin faces and extremely low IQs. But they're unusually sociable, and often display an extraordinary feeling for language. Ask a Williams child to name an animal, says Dr. Ursula Bellugi of the Salk Institute's Laboratory for Cognitive Neuroscience, and you may get a fanciful discourse on yaks, koalas or unicorns.

If we learned language in the same way that we learn to add, subtract or play cards, children like Barry would not get much beyond hello and goodbye. Nor, for that matter, would normal toddlers. As anyone who has struggled through college French can attest, picking up a new language as an adult is as simple as picking up a truck. Yet virtually every kid in the world succeeds at it-and without conscious effort. Children attach meanings to sounds long before they shed their diapers. They launch into grammatical analysis before they can tie their shoes. And by the age of 8, most produce sentences as readily as laughter or tears.

Scholars have bickered for centuries over how kids accomplish this feat, but most now agree that their brains are wired for the task. Like finches or sparrows, which learn to sing as hatchlings or not at all, we're designed to acquire certain kinds of knowledge at particular stages of development. Children surrounded by words almost always become fluent by 8, whatever their general intelligence. And people deprived of language as children rarely master it as adults, no matter how smart they are or how intensively they're trained. As MIT linguist Steven Pinker observes in his acclaimed 1994 book "The Language Instinct," "Language is not a cultural artifact that we learn the way we learn to tell time or how the federal government works. It is a distinct piece of [our] biological makeup." Whether they emerge speaking Spanish, Czech or Hindi, kids all acquire language on the same general schedule. And as a growing body of research makes clear, they all travel the same remarkable path.

Sound

THE JOURNEY TOWARD LANGUAGE STARTS NOT IN THE nursery but in the womb, where the fetus is continually bathed in the sounds of its mother's voice. Babies just 4 days old can distinguish one language from another. French newborns suck more vigorously when they hear French spoken than when they hear Russian--and Russian babies show the opposite preference. At first, they notice only general rhythms and melodies. But newborns are also sensitive to speech sounds, and they home in quickly on the ones that matter.

Each of the world's approximately 6,000 languages uses a different assortment of phonemes, or distinctive sounds, to build words. As adults, we have a hard time even hearing phonemes from foreign languages. The French don't notice any real difference between the th sounds in thick and then--and to most English speakers, the vowel in the French word tu (ee through rounded lips) is just another oo. Researchers have found that month-old infants register both of those distinctions and countless others from the world's languages. But at 6 and 10 months, they start to narrow their range. They grow oblivious to foreign phonemes while staying attuned to whatever sounds the speakers around them are using.