Around the year 1500, King James IV of Scotland ordered that a baby be raised in isolation to see what language he would develop if left on his own. The King speculated that the child would speak Hebrew, presumably the original tongue of all humankind. This experiment came to a bad end. The baby wasted away from lack of affection.
Today linguists agree that King James was wrong: a child is not born with knowledge of a specific language. We know that language develops as a child interacts with adults. However, exactly what happens in the process of language acquisition remains a matter of debate. Somehow, virtually all children acquire a means of communication so complex that no one has ever fully described the grammatical rules for even a single language.
How do children do it? It is possible that Project Washoe may indicate an answer. This project was an attempt to teach a form of human language, namely American Sign Language, or ASL, to a chimpanzee named Washoe. She acquired about 240 signs and produced them in sequences. Her progress in learning ASL could help answer the question by shedding light on the origins of language. Until she began signing, it was assumed that sometime after our ancestors diverged from Washoe’s ancestors about six million years ago, we evolved an anatomical structure that enabled us to develop language. But if Washoe could learn a human sign language it meant that the common ancestor of both humans and chimps also must have had the capacity for gestural communication.
What does this have to do with the mystery of child language acquisition? If we knew that our ancestors developed language through cognition and learning, then it follows that modern human children probably do the same thing. Children must use the same strategies to learn language — observation, imitation, and play — that they use to learn other skills, like tying their shoes or playing the piano. Language, of course, is more complicated than shoe tying and more universal than piano playing, so somewhere along the way humans must have developed a specialized way of learning in order to acquire language.
You may think that linguists welcomed Project Washoe’s attempt to map out a likely pathway for the evolution of human language. But this pathway pointed in a direction that utterly contradicted a theory of language acquisition that was widely accepted in the 1960s.
The theory, first advanced by Noam Chomsky, a well-known linguist at the Massachusetts Institute of Technology, argued that language is acquired independently from other cognitive abilities. According to him, the rules of language are so complex, and the adult speech is so disordered, that a child couldn’t possibly learn language by imitation. Instead, the rules of language had to be encoded in the brain.
Chomsky suggested that there is a “deep structure” of meanings that all languages have in common. Those meanings are transformed into the words of different languages by means of a “universal grammar.” He claimed that once this grammar was mapped out, it would reveal the logical properties that govern the infinite variety of Sentences that can be formed. This mapping task, however, proved almost impossible. Every time the “universal grammar” encountered a new language it had to be revised. One attempt to describe French in this fashion required twelve thousand items just to classify its verb structures.
Obviously, if a universal grammar did exist, no human two year-old would be able to learn such a complex system. So Chomsky suggested that every child is born with a “language acquisition device” that already has the universal grammar built in. According to Chomsky, the universal grammar was part of a child’s genetic makeup, making language unique to humans.
Chomsky said that the language acquisition device — or “language organ” — was located in the left hemisphere of the brain, but there is no anatomical evidence to support this. But anatomy aside, the language device was a reasonable hypothesis for explaining how children acquired language. What was not reasonable, however, was Chomsky’s suggestion that such a device was unique to humans. There simply wasn’t enough time, in the brief six million year period since humans diverged from apes, for evolution to add on a completely new brain structure. This “add on” scenario was at odds with the laws of biology. The primate brain did not evolve like an ever-expanding house, adding on new rooms as it grew from monkey ancestor to ape ancestor to human. Instead, evolution was continually reorganizing what it already had taking old structures and putting them to use for new mental tasks.
Supporters of the “language organ” theory still try to reconcile Chomsky’s theory with Charles Darwin’s theory of evolution. They argue that complex organs — the eye, for example — arise through an evolutionary process of natural selection. This is true, but organs such as the eye emerge over tens of millions of years not over a mere six million years. When it comes to closely related species that have recently descended from a common ancestor, one of them can’t possibly have enough time to develop an entirely new biological system. For example, if the African elephant has a trunk, you expect to find a trunk on its relative, the Indian elephant. The human and the chimpanzee descended from a common ancestor even more recently than the two elephant species. Finding a language organ in humans but not in chimps would be like finding a trunk on only one of the elephants.
From the viewpoint of biologists, this has always been the problem with the language acquisition device. Whenever we study its evolutionary development from ancestral species. Linguists, however, did not consider evolutionary constraints. They simply assumed a discontinuity between humans and apes and worked on the assumption that human language stood outside the animal kingdom. To Chomsky, human language bore no relation to any other form of animal communication.
It is easy to see how Chomsky reached this conclusion. He did not study language as social communication, namely, the face-to-face interactions between humans that integrate words, intonation, and body language. The way people speak is different from the visual grammar of ASL. In ASL I can color the sentence “I feel good” with different shades of meaning — from “cautiously good” to “unbelievably good” — by altering the height or speed of my sign. When speaking English, I can use tone and facial expression to color the word “good” with the same shadings.
By focusing on words on the page, Chomsky removed language from its social context. All the face-to-face signaling behaviors we share with chimpanzees were considered unimportant; the idea of a chimpanzee learning language was considered absurd. Chomsky said it was like an island of birds that had the power to fly but had never done so; if chimps had an innate capacity to use language, they’d already be talking in the wild.
Of course chimpanzees have been using gestural communication in the wild for millions of years, and their dialects of hand movement, facial expression, and body language look like the nonverbal elements of human language. Those of us in Project Washoe looked at chimpanzee gesture and saw the roots of human language. But Chomsky had already decided that human gesture is not linguistic. So whatever chimpanzees were doing in the wild, their gestural dialects could not be related in any way to human language.
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