Most linguists and cognitive scientists agree that we humans are uniquely blessed with the gift of language. Compared to human speech, animal calls are stereotyped and fixed, tied to specific situations such as mating, territorial claims, expressing aggression or raising alarm. The nearest equivalent to speech seems to come not from our nearest relatives, the great apes, but from birds. Parrots, for example, can imitate human speech, and even be taught to answer simple questions, like naming the colour of a block or counting the number of objects in a display (but only up to about six). Songbirds in the wild generate complex calls, but these are largely repetitive and probably serve primarily as identification codes. They have none of the individual variety that enables humans to express a virtually infinite range of ideas, thoughts and opinions.
For evolutionary theorists, the uniqueness of human language poses something of a problem. The seventeenth-century French philosopher René Descartes thought language so special that it must be a gift from God, and even materialistic scientists have sometimes supposed that there must have been some miraculous event—a fortuitous genetic mutation, perhaps—that gave us the gift of the gab.
My own solution—although not everyone agrees—is that language evolved, not from animal calls, but from manual gestures. Our great-ape cousins actually possess a much better range of manual gestures than of vocal sounds, and gesture naturally to each other in the wild. It is becoming clear, moreover, that their gestures are more deliberate and conversation-like than are their vocalisations. Attempts to teach captive chimps and bonobos to speak have been spectacularly unsuccessful, but some real progress has been made toward teaching them to communicate in a simplified form of sign language, or by pointing to symbols on a specially designed keyboard. It’s not true language, but it’s much more language-like than their attempts at speech.
We saw in the previous piece that our hominin forebears stood up on two legs and waved goodbye to the apes. This freed their hands from locomotory duty and, among other advantages, would have enhanced their ability to communicate manually. From over two million years ago, too, our industrious ancestors began to make stone tools, and this may have led to mimed communication about how tools work, and how to make them. Along with the development of tools, brain size increased dramatically. These developments probably signalled the emergence of a more elaborate group structure and complex communication, culminating in language, with its complexities of grammar and capacity to generate unlimited meanings.
If the gestural theory is correct, language must have switched from a manual to a vocal point at some stage in our evolution. This probably required further adaptations, including a lowering of the larynx in the neck, and a flattening of the face and shortening of the tongue. Fossil evidence suggests that these features were absent, or at least incomplete, even in the Neanderthals, depriving them of articulate speech. Jean Auel, in her novel The Clan of the Cave Bear, tells how Ayla, a Cro-Magnon girl, is orphaned after an earthquake and adopted by Neanderthals, who are capable of only limited speech but have a highly developed sign language. I like to think she is right about this. The Neanderthals had brains as least as large as our own, but died out some 30,000 years ago. We voluble humans may have somehow talked them out of existence.
So was this the terrible secret of sapiens? My guess is that it was not superior strength, or even superior brain power, that won the day. Rather, it was the late transition from gestural language to speech. So why should this transition have been so decisive—and indeed so destructive? Clearly, the advantages of speech over gesture were not linguistic, since sign languages are as linguistically sophisticated as vocal ones. The advantages were probably practical. Speech allows communication at night, or when the line of sight is impeded. Speech requires much less energy, since it effectively piggybacks on breathing, which we do anyway. Signing, in contrast, can be exhausting—instructors in sign-language courses, I’m told, often need regular massage to cope with the sheer physical demands.
Most importantly, though, speech allowed a second freeing of the hands. The retreat of communication into the mouth is an early example of miniaturisation, allowing the hands, and indeed the rest of the body, to be put to use in other activities, such as making and using tools, or carrying possessions around as our restless forebears moved from one location to another. This may account for the extraordinary explosion of technology (including weapons), art, bodily decoration and sheer cultural diversity that characterise our species. It also allowed our talkative forebears to explain manual skills while at the same time demonstrating them, as in modern cooking shows on television. These effects were no doubt cumulative, but in the course of time the gesturing Neanderthals never stood a chance.
Our technological advances, though, may have captured our hands once again, as we tap on our laptops, point laser-emitting devices at our televisions or tweet digitally on our cellphones. Perhaps we will need to find other ways to communicate with our devices, maybe by talking to them, or even through hooking up to direct measurement of brain activity. But whatever we do, our restless hands will no doubt always find new ways to occupy themselves—and we will continue to miniaturise, so that as fast as we find new things for our hands to do, we will find ways to relieve them again.
You may think it an odd idea that language was originally based on manual gestures, but note that deaf children can acquire sign languages just as easily and naturally as the rest of us learn to speak. Deaf kids even babble in sign. At Gallaudet University in Washington, DC, the official language is American Sign Language, and students study all the usual subjects—even poetry. And of course we all—but especially the Italians—gesture with our hands as we speak. The gestural origins of language are all around us.