The Evolution of Language, a Basic Primer

In accordance with my group’s topic on the evolution of language, I have chosen to focus on the transition from gestural communication to a system of vocalized speech in Homo sapiens. Taking advantage of the many studies conducted on non-human primates and their capacity for vocal and gestural expression, as well as discussing hominid evolution over the past six million years I intend to discuss the widely-accepted theory that vocalized communication developed out of primitive gestures as a result of natural selection. I also intend to discuss how this new system helped to ensure the survival and eventual dominance of Homo sapiens in Africa some 100,000 years ago.

Before delving in to the evolution of language, I feel it necessary to expound on the nature of language itself. When discussing the features that describe language, I turned to Charles Hockett, a prominent linguist, who wrote in 1960 that language in humans consists of six primary features. These features are as follows:

The first feature is that of semanticity. This is an elaborate way of saying that language uses words, signs, and symbols in order to represent different objects, actions, or concepts. These symbols should evoke a mental representation of the objects that they symbolize. The second feature is arbitrariness – this means that there does not have to be any sort of inherent relationship between the signified object and the signifier. The third feature is displacement – this means that we can use language in order to refer to objects or concepts not currently present in time or space. The fourth feature is productivity. Productivity refers to our ability to create an unlimited amount of unique sentences by combining the symbols in our shared lexicon. The fifth feature is syntax (or grammar), meaning that since the words in our vocabulary fall into different categories, in order to construct sentences we must assemble these words in the correct order. By changing the order of the words, we are then able to alter the meaning of the sentence. The sixth and final feature of language as proposed by Hockett is that of acquisition through traditional transmission. In other words, language is a learned phenomenon and is not inherited genetically. (Stross 55)

Taking all of these features into account, we can now begin to explore when and how language began to develop in Homo sapiens. It is a widely accepted belief that the split between hominids and the great apes occurred approximately 5 million years ago, thus, it is reasonable to assume that language developed sometime after the split between the hominids and the line that eventually led to the evolution of our closest ancestor, the chimpanzee. As with many aspects of human evolution, exactly when this occurred is a topic that has been hotly debated. Some theorists, such as Derek Bickerton of the University of Hawaii have argued that language did not develop until the arrival of the Homo sapiens in Africa a mere 150,000 years ago. This fact may help to explain why Homo sapiens eventually dominated and replaced all of the other members of the Homo genus, including Homo erectus and the Neanderthals. Yet another theorist, Philip Lieberman of Brown University, has argued that based on the available fossil evidence, modern linguistic capabilities did not evolve until late in hominid evolution, suggesting that even the Neanderthals would have been severely challenged vocally. This is a shocking claim to make, considering the Neanderthals did not die out until very recently – approximately 30,000 years ago. (Corballis 1999)

If we assume that language is, in fact, a recent acquisition produced through genetic mutations in our physiology and aided by natural selection, it follows logically that our system of communication might somehow be descended from our primate ancestors. Whether this answer lies in primate vocalizations (ie: alarm calls or emotional cries) or the primate gesture-call system remains to be seen. I intend to discuss these two possibilities in the following paragraphs.

One example of a possible link between human communication and primates comes to us through vervet monkeys. These monkeys exhibit three separate alarm calls, depending on which predator is visible: snake, eagle, or leopard. Even though it is true that early hominids may have used such calls in order to communicate, these calls are not considered a language, as they do not abide by the rules of Hockett’s description. The vervet calls have meaning within themselves and cannot be recombined to form new expressions. In addition, since human beings are directly descended from great apes and it has been shown that apes do not, in fact, use this alarm-call system, it is impossible for vervet monkey calls to be the direct precursor to human language. (Cangelosi 1967.)

In order to better understand how our system of language developed, let us first take a look at primate evolution. Primates are largely visual creatures – vision is their best-developed sense and provides many obvious advantages when dealing with predators, competition for food, and general intelligence. Also, with the exception of humans, many primates are much better at voluntarily controlling their hands and arms than they are at controlling their vocal cries. We can deduce from this that the earliest hominids would have certainly been much better adapted for expressive communication using their hands. This might also explain why attempts to teach sign language to chimps has been much more successful that attempts to teach vocal communication. (Kojima 1943)

Although primates are adept at using their arms to voluntarily communicate, they are also reliant on them for many other things, including locomotion and postural support. Most primates are adapted for life in the trees and use their arms to swing from branches. Chimps and gorillas adopt a form of “knuckle-walking” where the upper body is supported by the knuckles. In contrast, a unique characteristic of hominid evolution is the development of bipedalism, a system of walking that involves an upright stance and makes no use of the arms for support. This trend, though widely debated as to how it arose, dates back to around four million years ago. Hands now became free to use for other purposes, among them possibly tool-use as well as expressive communication. (Corballis 1999)

When the hominids and the great apes split, the hominids now found themselves in a savannah-like environment. Here the early hominids would have been subject to many predators – early incarnations of lions, tigers, and hyenas. They needed to develop an effective system of communication in order to avoid predators. This may have led to the proliferation of manual expressive gestures. These gestures provided a great advantage, as they were silent, spacial (ie: able to convey information about where something was, such as a carcass to be eaten, or predator to avoid), and very iconic in that the gestures bore a significant relationship to the object which they were signifying. (Corballis 1999)

The question then remains: if our early ancestors developed a system of communication based on visual, manual gestures, then why do modern-day human beings speak? The answer is not an easy one, but many theorists believe that it was a natural, gradual transition from gesture to spoken language. It is unlikely that this shift was sudden – vocalized squeals and grunts must have punctuated early manual gestures just as gestures today often complement vocal communication. After all, there are many beneficial aspects to adopting a vocalized system of communication: speech can be carried on in the dark, or over large distances. More importantly, speech would have freed the hands yet again for things such as tool-use, whereby an experienced person could both demonstrate a tool’s ability while being able to give directions at the same time. This may be the reason why Homo sapiens eventually came to dominate and replace all other hominid species. Obviously, this shift required a change in physiology – and it has been suggested that these changes did not occur until late in hominid evolution approximately 100,000 to 150,000 years ago. (Corballis 1999)

Works Cited:

Cangelosi, Angela (ed.) Simulating the Evolution of Language. Springer. London, 1967. 328-337.

Corballis, Michael C. “The Gestural Origins of Language.” American Scientist. Volume 87. No. 2. 1999.

Kojima, Shozo. A Search for the Origins of Human Speech: Auditory and Vocal Functions of the Chimpanzee. Kyoto University Press. Kyoto. 2003.

Stross, Brian. The Origin and Evolution of Language. University of Texas. WMC Brown Company Publishers.Dubuque, Iowa. 1976. 54-56.

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