A biological view of the human language Abridged from Early Voices: The Leap to Language by Nicholas Wade, originally appearing in the July 15, 2003, edition of The New York Times Lower birds are artists, leaf-cutting ants practice agriculture, crows use tools, chimpanzees form coalitions against rivals. The only major talent unique to humans is language, the ability to transmit encoded thoughts from the mind of one individual to another. Because of language's central role in human nature and sociality, its evolutionary origins have long been of interest to almost everyone, with the curious exception of linguists. Many linguists have avoided the subject because of the influence of Noam Chomsky, a founder of modern linguistics and still its best-known practitioner, who has been largely silent on the question. In defense of the linguists' tepid interest, there have until recently been few firm facts to go on. Experts offered conflicting views on whether Neanderthals could speak. Sustained attempts to teach apes language generated more controversy than illumination. But new research is eroding the idea that the origins of language are hopelessly lost in the mists of time. New clues have started to emerge from archaeology, genetics and human behavioral ecology, and even linguists have grudgingly begun to join in the discussion before other specialists eat their lunch. Geneticists reported in March that the earliest known split between any two human populations occurred between the !Kung of southern Africa and the Hadza of Tanzania. Since both of these very ancient populations speak click languages, clicks may have been used in the language of the ancestral human population. The clicks, made by sucking the tongue down from the roof of the mouth (and denoted by an exclamation point), serve the same role as consonants. That possible hint of the first human tongue may be echoed in the archaeological record. Humans whose skeletons look just like those of today were widespread in Africa by 100,000 years ago. But they still used the same set of crude stone tools as their forebears and their archaic human contemporaries, the Neanderthals of Europe. Then, some 50,000 years ago, some profound change took place. Settlements in Africa sprang to life with sophisticated tools made from stone and bone, art objects and signs of long distance trade. That genetic change, he suggests, was of such a magnitude that most likely it had to do with language, and was perhaps the final step in its evolution. If some neural change explains the appearance of fully modern human behavior some 50,000 years ago, "it is surely reasonable to suppose that the change promoted the fully modern capacity for rapidly spoken phonemic speech," Dr. Richard Klein of Stanford University has written. Language, as linguists see it, is more than input and output, the heard word and the spoken. It's not even dependent on speech, since its output can be entirely in gestures, as in American Sign Language. The essence of language is words and syntax (the hierarchical ordering of words in a sentence to govern their meaning), each generated by a combinatorial system in the brain. Chimpanzees do not seem to possess either of these systems. They can learn a certain number of symbols, up to 400 or so, and will string them together, but rarely in a way that suggests any notion of syntax. This is not because of any poverty of thought. Their conceptual world seems to overlap to some extent with that of people: they can recognize other individuals in their community and keep track of who is dominant to whom. But they lack the system for encoding these thoughts in language. How then did the encoding system evolve in the human descendants of the common ancestor of chimps and people? Dr. Michael Corballis, a psychologist at the University of Auckland in New Zealand, believes the gesture came first, in fact as soon as our ancestors started to walk on two legs and freed the hands for making signs. Chimpanzees have at least 30 different gestures, mostly used to refer to other individuals. Hand gestures are still an expressive part of human communication, Dr. Corballis notes, so much so that people even gesticulate while on the telephone. He believes that spoken words did not predominate over signed ones until the last 100,000 years or so, when a genetic change may have perfected human speech and led to its becoming a separate system, not just a grunted accompaniment for gestures. Critics of Dr. Corballis's idea say gestures are too limited; they don't work in the dark, for one thing. But many concede the two systems may both have played some role in the emergence of language. In the mere six million years since chimps and humans shared a common ancestor, this highly complex faculty has suddenly emerged in the hominid line alone, along with all the brain circuits necessary to map an extremely rapid stream of sound into meaning, meaning into words and syntax, and intended sentence into expressed utterance. Researchers contend that many components of the language faculty exist in other animals and evolved for other reasons, and that it was only in humans that they all were linked. This idea suggests that animals may have more to teach about language than many researchers believe, but it also sounds like a criticism of evolutionary psychologists who seek to explain language as a faculty forced into being by specifics of the human lifestyle. Dr. Chomsky rejects the notion that he has discouraged study of the evolution of language, saying his views on the subject have been widely misinterpreted. He outlined his views briefly in lectures 25 years ago but left the subject hanging, he said, because not enough was understood. He still believes that it is easy to make up all sorts of situations to explain the evolution of language but hard to determine which ones, if any, make sense. Others see Dr. Chomsky's long silence on evolution as more consequential than he does. "The fact is that Chomsky has had, and continues to have, an outsize influence in linguistics," Dr. Steven Pinker, a cognitive neuroscientist at Massachusetts Institute of Technology, said in an e-mail message. Dr. Pinker noted that Chomsky "has rabid devotees, who hang on his every footnote, and sworn enemies, who say black whenever he says white." "That doesn't leave much space," Dr. Pinker went on, "for linguists who accept some of his ideas (language as a mental, combinatorial, complex, partly innate system) but not others, like his hostility to evolution or any other explanation of language in terms of its function." Biologists and linguists have long inhabited different worlds, with linguists taking little interest in evolution, the guiding theory of all biology. But the faculty for language, along with the evidence of how it evolved, is written somewhere in the now decoded human genome, waiting for biologists and linguists to identify the genetic program that generates words and syntax. Nicholas Wade