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Chapter 1: The Greatest Intellectual Feat
Chromosomes. Sex. Grasshoppers. "Pick me up, Mommy."
This is an odd list, except in the eye of evolution. For in the major developments in the history of life, the ability to say, "Pick me up, Mommy" features prominently along with the emergence of genes, sexual reproduction, and multicellular organisms. On a smaller but no less wondrous scale, the ability to speak opens one mind to another. Babies announce their arrival with a loud cry, but it is their first words that launch the journey of a lifetime:
This is the miracle of language, the ability to arrange sounds into infinitely many ways to convey infinitely varied meanings. Language is what we use to tell stories, transmit knowledge, and build social bonds. It comforts, tickles, excites, and destroys. Every society has language, and somehow we all learn a language in the first few years of our lives, a process that has been repeated for as long as humans have been around. Unlike swimming, using Microsoft Windows, or making the perfect lemon souffle; -- which some of us never manage to do -- learning a language is a task we can all take for granted.
Although every form of life is a testament to the power of evolution, language is an achievement of humans, and humans alone. The talents for cooperative hunting, tool making, and having sex for fun, once thought to be unique to us, have all been found in other species. However, as far as we know, there is nothing like language in the vastly varied systems of communication in other animals, which makes it a lasting -- and perhaps the last -- grip for our anthropocentric arrogance. The centrality of language to human nature is what prompted the great French thinker Rene; Descartes to separate men from beasts:
It is a very remarkable fact that there are none so depraved and stupid, without even excepting idiots, that they cannot arrange different words together, forming of them a statement by which they make known their thoughts; while, on the other hand, there is no other animal, however perfect and fortunately circumstanced it may be, which can do the same.
Just how do we do this?
My son, Russell, had just turned three when I started writing this book. A medium-sized newborn, he soon shot off the growth charts that now populate parenting books. At three, he was wearing size five. However, Russell was rarely mistaken for a five-year-old. When he ran, he still waddled. Although he could throw, he couldn't catch. And he still couldn't tie his shoes. Children develop along a fairly consistent schedule, which leaves landmarks of physiological attributes and abilities. If you watched Russell in the playground, you would see just an unusually large specimen among three-year-olds.
But you didn't need to see him at the playground to know Russell was just three. Every waiter or waitress who greeted us was successful at guessing his age. As soon as Russell started insisting on pizza over anything else on the menu, his language betrayed his age. What his words sounded like and how they were put together are familiar to anyone who has been around kids.
Much like motor skills and head-to-body ratio, language also develops along a fairly consistent schedule. Out of the cries, coos, and laughs, all infants start babbling around the eighth month. Deaf babies babble too -- with their hands. For children learning to speak English, the first words more or less coincide with the first birthday, and sentences -- the arrangement of words -- start appearing when the child is a year and a half. By age three, most children know over a thousand words. They have command of many complex sentence structures, and can carry out fully independent and undeniably cute conversations with adults. And similar successive stages show up not only in English-speaking children, but also in those learning to talk in French, German, Chinese, and Swahili.
All children learn a language and they do so in similar ways. This, coupled with the fact that language learning occurs only in human youngsters, suggests that the root of language is in our biology. There is something in our genes that other species don't have, which is why a child's puppy, which grows up in the same household and hears the same sounds, never learns the language that the child learns.
Claiming language to be uniquely human may sound like a desperate attempt to assert our special place in nature: the latest count shows that chimpanzees share 96 percent of our genes. But every species is a unique product of biological evolution. Bats can find their way in the dark. Squirrels can hide and find thousands of nuts to pass the winter. Frogs are far better than us at catching mosquitoes. Biologically speaking, language is no more special than any of these abilities; what is special is the things that humans have done with language, including writing and reading books on how language is learned. Thus, Charles Darwin, the ultimate destroyer of our self-importance, didn't hesitate to remark that "Man has an instinctive tendency to speak, as we see in the babble of young children, whilst no child has an instinctive tendency to bake, brew, or write." Furthermore, humans' specialty for language is not at odds with biological evolution. As Darwin notes, "the faculty of articulated speech does not in itself offer any insuperable objection to the belief that man has developed from some lower form."
But a biological basis cannot be all there is to language. Learning a language is not like walking, which is simply (and automatically) a matter of neuromuscular maturation, occurring around a child's first birthday. Again, in Darwin's words, language "is not a true instinct, for every language has to be learnt." After all, English children grow up speaking English, and Chinese children, Chinese. And for a lot of people, the most impressive thing about languages is how different they seem. This means that the neural hardware for language must be plastic; it must leave space and possibilities to respond to the particular environment a child is born into, and to result in different organizations of the brain for different speakers. To put it simply, language learning requires both nature and nurture.
This book explains how nature and nurture work together to give children language. To develop such an explanation, one necessarily faces many obstacles that are not present in other disciplines; there can be no poking around in a child's brain, for instance. An indirect route of research must be sought when direct tampering with a child's nature or nurture is not possible. And a useful clue may be found just outside your bedroom window.
Songbirds constitute the largest order of birds in the world, and their songs vary considerably across species and even by geographical location. Think of these as English vs. Chinese, Harvard accent vs. Texas twang.
Chicks do not start singing at birth: songs have to be learned. The onset of learning is a period of listening to adult songs and memorizing them for later use. This is followed by a stage of unstructured chirps: the chick experiments with its vocal organs.
But then song learning takes off. The youngsters quickly become specialized in their native songs and dialects; by then, avid birders can identify their species and origin by their songs alone. For some birds, a period of creativity follows. The bird may thump out a few variations, all of which are potentially songs native to the species, but only those unique to the geographical region are eventually retained.
Birdsong learning is the work of both nature and nurture. Of all the acoustic events in its environment, a young songbird can somehow pick out the songs of its own kind: songbirds don't learn from ducks or hawks, for instance. In an experiment, chicks were hatched in a laboratory so that they had no experience with adult songs whatsoever. They were then exposed to the recorded songs of their own species as well as others. Remarkably, a strong preference for the native tunes was discovered; this affinity must then have come from the genome.
At the same time, songs that are unique to a species must be learned from experience. A songbird that grows up without ever hearing adult birds of its own species never sings. In addition, songs can be learned only if the experience comes within a sensitive period as the bird matures; this window of opportunity then shuts permanently. The chaffinch, for instance, cannot learn new songs after the tenth month.
Birdsong learning and language learning have unmistakable parallels. Human infants aren't born talking either, but they come fully prepared. Somehow babies can tune out radios, telephones, and their sibling's tantrums and zero in on the sounds of speech. Just as songbirds listen and store up their adult songs, babies quietly register many specific features of their language in the beginning of language learning. Babbling is babies' experimentation with their vocal organs. While young children's speech may sound imperfect to adults, there is no doubt that the children are working on the language that they will eventually attain. After all, children generally understand us (though sometimes it does seem that they pretend not to). And when Russell says:
"The sun is sweating you"
"Super Grover flied away"
he is not just mimicking adults, who would never talk that way. Children, like some songbirds, are innovators, not just imitators.
No scientist has reared a child in a laboratory in isolation, but the necessity of experience for language learning cannot be doubted. The ultimate experiment, so the legend goes, was carried out by Psamtik I, who ruled Egypt in the seventh century BC. As told by the Greek historian Herodotus, the king wanted to know which people were the most ancient in the world, a distinction he thought could be identified by seeing who used the most ancient language. He gave two newborn babies to a shepherd, who was responsible for their survival but forbidden to utter any word in their presence. The king reasoned that the "original" tongue would come out if the child was not polluted by inferior languages.
The first word that came out, the legend continues, was becos: it meant "bread" in Phrygian, which was the language, now extinct, spoken in what is modern-day Turkey. Psamtik thus conceded that the Phrygians, speakers of the original tongue, were an older people than the Egyptians. No one is sure whether these events actually happened, and of course, if they did, the king's conclusion would not pass a scientific journal's review board. He failed to establish the premise of his cruel experiment: the king apparently assumed that language could be learned without experience.
A wild boy was found in 1798 who had somehow survived after having been abandoned in the woods. He was believed to be eleven. Jean-Marc Gaspard Itard, a French physician and pioneer of special education, did everything to guide him back to a normal life, including "to lead him to use of speech by inducing the exercise of imitation." He never spoke, but always responded "Oh" when Itard said "Victor," so the boy became known as Victor. Itard eventually gave up:
Finally, however, seeing that the continuation of my efforts and the passing of time brought about no change, I resigned myself to the necessity of giving up any attempt to produce speech, and abandoned my pupil to incurable dumbness.
In 1920, two children were captured in India by a hunting party fearful of ghostly figures roving in the woods. Later christened Amala and Kamala, they had been reared by wolves (some say leopards). Amala, one and a half when discovered, died soon afterward; Kamala, eight, lived until the age of seventeen. In five years, Kamala learned about thirty words; normal children learn that many in three days. Her vocabulary improved a little in later years, and she could respond to simple commands, but there was no spontaneous or novel use of sentences.
Each story of wild children is a tragedy of deprivation; some are almost too painful to describe. Each reaches the same somber conclusion: no experience, no language. And the experience has to come early enough. Indeed, wild children were given their own place, a subdivision within Homo sapiens by Carl Linnaeus, the great classifier of life: Homo ferus (feral, or "wild man"), whose defining characteristics include "mute."
There are obviously differences between song learning and language learning. Birds don't speak, and we don't chirp. Nevertheless, the characteristics of song learning and language learning are strikingly similar, suggesting that neurological growth during learning may involve mechanisms common to humans and birds. Indeed, that's the theme of this book: language learning takes something old and something new.
Nature doesn't build things from scratch.The gift of language is the latest step that led to the rise of Homo sapiens, but this great leap forward must have been preceded by many other strange turns in the history of life. Evolution is a thrifty tinkerer, recycling and reusing old parts, and when a new piece of equipment arrives, it has to work together with existing structures. The gift for language, therefore, must build upon and interact with other cognitive and perceptual systems that existed before language and are partially shared with other species. Without the auditory system, we could not hear; without the vocal tract, we could not talk; without the capacity to understand the world and ourselves, we'd have little to talk about; without complex social structures and networks, we'd have no one to talk to. And to such a list of prerequisites, we can add this: ancient neural mechanisms that helped numerous species to survive in a constantly changing environment. The gift of language is the foundation for arts, science, and other crowning achievements of human civilization, but as we shall learn in this book, the process by which children master the gift is the decidedly lowbrow biology that guides birds to seeds in the woods and rodents through mazes in psychology laboratories.
This book is about the science of how children learn language. Curiosity about language learning didn't start with modern linguistics. In all likelihood, it started out with parents who paused to think about their children's achievements. We have always wondered what language is and what it comes from, much the same as we are concerned with our nature and origin; with the Tower of Babel, the Bible offers an account for both. The raw materials for the study of child language initially came from diaries of linguists who kept track of children's speech. One of the earliest was published in the 1880 Transactions of the American Philological Association, fittingly entitled "A contribution to infantile linguistics." My wife and I -- we are both linguists -- often jot down fabulous sentences when Russell talks.
The science of language learning took off only when linguistics was revolutionized by Noam Chomsky. Chomsky became the first in modern times to give children the credit they deserve in learning a language. He writes:
The child who learns a language has in some sense constructed the grammar for himself on the basis of his observation of sentences and nonsentences (i.e. corrections by the verbal community). Study of the actual observed ability of a speaker to distinguish sentences from nonsentences, detect ambiguities, etc., apparently forces us to the conclusion that this grammar is of an extremely complex and abstract character, and that the young child has succeeded in carrying out what from the formal point of view, at least, seems to be a remarkable type of theory construction. Furthermore, this task is accomplished in an astonishingly short time, to a large extent independently of intelligence, and in a comparable way by all children. Any theory of learning must cope with these facts.
The only way for children to learn something as complex as language, Chomsky contends, is to have known a lot about how language works beforehand, so that a child knows what to expect when immersed in the sea of speech. In other words, the ability to learn a language is innate, hidden somewhere in our genes. Leonard Bloomfield, who ruled the academy of linguistics before Chomsky took it by storm, was in perfect agreement with his successor on one critical point. As a scholar who was intimately familiar with the complexity of the world's languages, Bloomfield once remarked that learning a language "is doubtless the greatest intellectual feat any one of us is ever required to perform." One of the consequences is that we need a whole book to explain "Kitty," "Big drum," and "Drink tea."
One more note before we begin: this is not a parenting book. As a young father, I understand parents' anxiety about their children's development, but this book will not tell you how to help your child learn a language. As far as language is concerned, your child doesn't need help. You do not need to make a special effort for your child's language development; all you need to do is talk to him or her as loving parents. You will see that children are infinitely better at learning languages than we are, and why. And you will see that the "errors" in their speech are inevitable and will go away in due time.
Now, let's see why language "is of an extremely complex and abstract character," and why learning a language, as effortless as it looks, is indeed our greatest intellectual feat.
Copyright ©2006 by Charles Yang