How Children Learn to Talk: Two Views of Language

One of the most remarkable achievements of early childhood is also one of the most familiar: learning to talk. In the space of a few short years, and without any formal teaching, almost every child comes to understand and produce a language of astonishing complexity, mastering thousands of words and an intricate system of rules for combining them. Children do this at an age when they cannot yet tie their own shoelaces, and they do it whatever language surrounds them. Children also make the same kinds of mistakes as they go, and pass through broadly the same stages, whether they are raised in a bustling city or a quiet village, and whether the language around them is spoken by millions or by only a few hundred. How this feat is accomplished has been one of the central questions of the study of the mind, and it has produced two very different schools of thought.

The first of these is associated above all with the linguist Noam Chomsky, whose ideas dominated the field for much of the twentieth century. Chomsky argued that the human capacity for language cannot be explained by general intelligence or ordinary learning alone. Human beings, he proposed, are born with an innate, specialised capacity for language, a kind of mental equipment dedicated to grammar that is unique to our species. Underlying all the thousands of different human languages, on this view, is a single deep structure, a 'universal grammar', which every child already possesses at birth and which allows them to acquire whatever particular language they happen to be exposed to.

A central pillar of this argument is what Chomsky and his followers call the 'poverty of the stimulus'. The everyday speech that children hear, they point out, is fragmentary, full of slips, false starts and incomplete sentences, and it simply does not contain enough information to explain the rich and consistent grammatical knowledge that children reliably end up with. If the input is so limited and yet the outcome so uniform, they argue, then much of the underlying structure of language must already be present in the child's mind before a single word is heard. Children are not so much taught language, on this account, as programmed to grow it, in the way that they grow teeth.

A second, more recent school of thought challenges this picture at almost every point. Researchers in what is often called the usage-based tradition, whose leading figures include the psychologist Michael Tomasello, argue that there is no need to assume a special, dedicated language faculty at all. Children, they contend, learn language in much the same way as they learn other complex skills: through social interaction, imitation and the powerful general-purpose learning abilities of the human brain. On this view, language is not a separate mental organ but the product of ordinary cognition applied to an extraordinarily rich social environment.

Central to the usage-based account is the role of interaction. Children do not encounter language as a stream of disembodied sentences to be analysed; they experience it embedded in shared activities with caring adults, who point, name, repeat and respond. From this rich social exchange, and by tracking the statistical patterns in the speech they hear, children gradually work out how their language behaves. Where the nativists see a limited stimulus, the usage-based researchers see an abundant one, full of the cues a socially attuned learner needs. The regularities of grammar, they argue, can emerge from this process without being built into the mind in advance.

The debate between these two traditions has been long and often fierce, and it is far from settled. Both sides agree on the basic facts, that children learn language early, quickly and with little explicit instruction, but they disagree profoundly about what those facts imply. Is the human child a specialised language machine, equipped from birth with the essentials of grammar, or a brilliant general learner making sense of a rich social world? The question matters well beyond the study of childhood, for it touches on what is distinctive about the human mind itself, and on how much of what we become is written into us before we begin, and how much we assemble from the world around us.