In recent years neuroscientists have begun to get a picture of what is happening in a baby’s brain during the process of learning language that takes the child from a gurgling newborn to a wonderfully engaging youngster.

At birth, the infant brain can perceive the full set of 800 or so sounds, called phonemes, that can be strung together to form all the words in every language of the world. During the second half of the first year, research shows that a door opens in the child’s brain. The baby enters a “sensitive period,” as neuroscientists call it, during which the infant brain is ready to receive the first basic lessons in the magic of language.

The built-in capacity for language does not on its own propel the child past the first utterances of “mama” and “dada.” To learn this most important of social skills requires that a baby pay careful attention to countless hours of parent-speak. Insights from research into early language acquisition have reached a degree of sophistication that has enabled neuroscientists to contemplate the possibility of using brain recordings to test whether a child’s brain is developing as it should.

Leading researcher Patricia Kuhl writes about how children learn language in “Baby Talk,” which appears in the November Scientific American. After you’ve read the article, watch Kuhl give a TED talk on this topic: