Trying to discover the origins of language is a fascinating scientific problem but the evidence is necessarily indirect. Clearly our bodies’ physical capacity to articulate sounds is a biological development. Language had to be preceded by the evolution of the physical organs responsible for vocalization. Those organs must have co-evolved with those parts of the brain that can process language. But this evolutionary history is hard to reconstruct since the voice organs and brains are made of soft tissue and are thus unlikely to fossilize. Even if we could get an accurate fix on when the actual physical ability to speak came into being, this the could only be used to set a limit on the earliest time at which language could have occurred, but tells us nothing of when it actually did.

Since humans have these language organs and our closest existing cousins the chimpanzees do not, and since our branch of mammals split off from chimpanzees about 5-7 million years (or about 350,000 generations) ago, it is theoretically possible for language to be that old and still be consistent with only humans being able to speak.

At the other end, the discovery of cave art in Europe consisting of depictions of animals and humans in carved and painted and sculpted forms by Cro-Magnon humans in the Upper Paleolithic era about 35,000 years ago indicate complex social thinking indicative of the presence of language, suggesting that this sets a limit on the latest time for the origin of language.

But 35,000 to 5-7 million years is a huge time interval and attempts have been made to get a more precise fix on the origin of language. Various approaches have been attempted. One avenue of exploration comes from linguistics: the study of languages themselves and how they evolved. Another is to look at the physiological development of the human body. A third method is to look at the development of lifestyles to discern levels of complexity that suggest the kinds of social organization that would require language. A fourth is to look at the use of tools, to see if there is sophistication and uniformity over a wide area suggesting that knowledge was being shared and transmitted to distant locales.
While these are all promising avenues of research, unfortunately the lines of evidence from these different approaches currently do not converge on a single time, suggesting that we still have a long way to go in determining when language might have arisen.

Starting with linguistics, it is known that the structure of languages is very analogous to the biological tree of living organisms. Just as the fossil and DNA evidence all point to all living things being descended from a common ancestor, the approximately five thousand languages that currently exist exhibit grammar and vocabulary relationships strongly suggestive of the fact that they are all derived from a single common proto-language that existed long ago that evolved and split into branches the way that living organisms did. By tracing that linguistic tree back in time, we may be able to fix narrower bounds on the date of origin of that proto-language.

Steven Pinker argues that since modern humans Homo sapiens first appeared about 200,000 years ago and spread out of Africa about 100,000 years ago, and since all modern humans have identical language abilities along with a universal grammar, it seems likely that language appeared concurrently with the first appearance of modern humans. (Steven Pinker, The Language Instinct, 1994, p. 363, 364) Furthermore, there was a more than a tripling of brain size (from 400cc to 1350cc) during the period between the first appearance the genus Homo (in the form of Homo habilis) about two million years ago until Homo sapiens appeared, suggesting that the brain developed in that period partly in order to accommodate the new language centers. Pinker suggests that since Homo sapiens are us, it seems reasonable that language came into being as long ago as 200,000 years ago.

As for biological development. Richard Leakey explains what it is about the human body that enables speech. (The Origin of Humankind, 1994)

Humans are able to make a wide range of sounds because the larynx is situated low in the throat, thus creating a large sound-chamber, the pharynx, above the vocal chords . . . the expanded pharynx is the key to producing fully articulate speech . . . In all mammals except humans the larynx is high in the throat, which allows the animal to breathe and drink at the same time. As a corollary, the small pharyngeal cavity limits the range of sounds that can be produced. . . Although the low position of the larynx allows human to produce a greater range of sounds, it also means that we cannot drink and breathe simultaneously. We exhibit the dubious liability for choking.

Human babies are born with the larynx high in the throat, like typical mammals, and can simultaneously breathe and drink, as they must during nursing. After about eighteen month, the larynx begins to migrate down the throat, reaching the adult position when the child is about fourteen months old. (p. 130)

The unique position of the larynx in human speech suggests that if were able to identify when it got lowered to its present position, we might be able to determine when we first had the ability to speak. But the problem is that those parts of the body are made of soft tissues and do not fossilize easily. However, the shape of the bottom of the skull called the basicranium is arched for humans and essentially flat for other mammals and this part of the skull is an indicator of how well it can articulate sounds. “The earliest time in the fossil record that you find a fully flexed basicranium is about 300,000 to 400,000 years ago, in what people call archaic Homo sapiens.” (Leakey, p. 132)

But of course that does not mean that language developed simultaneously with the basicranium. Leakey says that it is unlikely that language was fully developed among archaic Homo sapiens.

The brain is another indicator of possible language origins. The part of the brain known as Broca’s area is a raised lump near the left temple associated with language and the use of tools. Furthermore, the left hemisphere of the brain (which is associated with language) is larger than the right. So if we can find fossilized skulls that indicate the presence of either of these features, that would also indicate the onset of possible linguistic ability. A fossil found nearly two million years ago seems to have just such features. Combined with the discovery of tool-making around this time Leakey thinks it is possible that it was with the advent of Homo habilis (the handyman) about two million years ago that language first started to appear, at least in a very crude form. (Leakey, p.129)

Another strategy is to look at the various tools and other artifacts that humans created and see if there is an increase in sophistication and increased spread of similar designs, which would suggest the sharing of knowledge and ideas and thus speech. The more complex the social structures in which people lived, the greater the need for language. As for tools, although they started being made about two million years ago, the earliest kinds were opportunistic in nature. More conscious tool making began about 250,000 years ago but then stayed static for about 200,000 years. The kinds of ordering of tools that are really suggestive of language does not seem to occur until suddenly about 35,000 years ago, coinciding with the sudden spurt in cave art in the Upper Paleolithic period. (Leakey, p. 134)

So basically the situation is confused. While it is possible that language began to appear in some primitive form as early as two million years ago, it seems more likely that real language skills began about 200,000 years ago. Also it is not clear whether language evolved gradually since that time or whether it remained in a low and more-or-less static state before suddenly exploding about 35,000 years ago into the complex language structures that we now have.

Next: Can animals talk?

POST SCRIPT: Fred and Wilma? Who knew?

The most unforgettable act of the 1969 Woodstock festival was Joe Cocker’s rendering of the Beatles’ A little help from my friends, a gentle song sung by Ringo Starr, which Cocker turned into an over-the top, weird, air-guitar-playing, frenzied, incoherent performance that looked like he was having some kind of seizure. Throughout it, you kept wondering what the hell he was singing since the lyrics seemed to have only a passing resemblance to the original.

Some helpful soul has now provided captions for Cocker’s words. It all makes sense now. Or maybe not.

(Thanks to Jesus’s General.)

One of the things that makes some people uneasy about the theory of evolution is its implication that humans are just one branch in the tree of life, connected to every other living thing through common ancestors, and thus not special in any mysterious way. It is surely tempting to think that we must be somehow unique. Look at the art and culture and science and technology we have produced and for which nothing comparable exists by any other species. How can we explain that if we are not possessed of some quality not present in other species?

One doesn’t have to look far to find one feature that distinguishes the human species from all its cousins in the evolutionary tree of life. It is language. Somehow, at some point, we developed the capacity to speak and communicate with each other through well-articulated sounds and that has had a profound impact on our subsequent development. Although the number of phonemes (units of sound) that humans can make (about fifty) is not vastly greater than the number available to apes (about a dozen), we can use them to generate an average vocabulary of about 100,000 words. “As a consequence, the capacity of Homo sapiens for rapid, detailed communication and richness of thought is unmatched in the world of nature.” (Richard Leakey, The Origin of Humankind, 1994, p. 122)

Without language, the knowledge of animals is restricted to what they are born with as a result of their evolutionary development (i.e., their instincts) and what they acquire during their own lifetimes. That is necessarily restricted and each generation essentially starts life at the same point in knowledge space as the previous one.

But with language, all that changes. Now knowledge can be passed on from generation to generation and we can learn from our ancestors. Knowledge becomes cumulative and the process accelerated with the discovery of writing about 6,000 years ago, resulting in the ability to store and retrieve knowledge over long times and long distances.

I have sometimes wondered why religious people, always on the lookout for a sign that humans are special in god’s eyes and possessed of some quality that could not be accounted for evolutionarily, have not seized on language as that which makes us uniquely human. Why don’t intelligent design advocates suggest that it was god’s intervention that enabled us to develop the ability to speak?

One advantage to religious people of using the introduction of language as a mysterious sign of god’s actions is that it is hard to pin down exactly when and how language started, and thus might make it hard to explain scientifically, making it an even better choice for a religious explanation than the bacterial flagellum or even the origin of life. Language was a significant development in our evolutionary history but how it came about is murky because spoken language leaves no trace.

Of course, the fact that we humans possess a unique feature does not necessarily imply that we are special. After all, elephants can also boast of a uniquely useful organ, the trunk, that can do truly amazing things. It is strong enough to uproot trees and stack them carefully in place. It is delicate enough that it can pick a thorn, draw characters on paper with a pencil, or pick up a pin. It is dexterous enough that it can uncork a bottle and unbolt a latch. It is sensitive enough to smell a python or food up to a mile away. It can be used as a siphon and a snorkel. And it can do many more things, both strong and delicate. (Steven Pinker, The Language Instinct, 1994, p. 340)

Why did only elephants evolve this extremely useful organ compared to which the human nose seems so inadequate? It presumably developed according to the laws of natural selection, just like everything else. But if elephants were religious, they might well be tempted to argue that having a trunk was a sign from god that they were special and made in god’s image, and thus that god must have a trunk too.

So uniqueness alone doesn’t imply that we are possessed of some spiritual essence. But even if the ability to speak does not confer on us a mystical power, the question of when and how humans developed this profound and incredibly useful ability is well worth studying.

Next: When did language originate?

POST SCRIPT: George Carlin on language

I had written this post on language last week but then learned that comedian George Carlin died yesterday at the age of 71. He pushed the boundaries of comedy and many of his riffs dealt with the hypocritical use of language. His famous routine “Seven words you can’t say on TV” ended up in 1973 as a case in the Supreme Court, which ruled that the government did have a right to limit the words used on broadcasts.

That routine is below. As to be expected, there is extensive and repeated use of the seven naughty words so don’t watch if such language offends you.

Bonus video: George Carlin was also an atheist who poked fun at the lack of logic underlying religious beliefs.

(I will be away on travel this week so will be reposting an old series, edited and updated, that discusses the nature of science and the difference between science and religion. New posts start again on Monday, April 21, 2008.)

In the previous posting, I discussed some of the problems that arise is reconciling science and religion. These problems change with time as our understanding of science changes and the explanatory powers of science encompass more and more phenomena.

For example, in the pre-Copernican era, one could have had a plausible model of god that became much harder to sustain in the light of post-Copernican scientific developments. This was because the universe then was seen as consisting of a spherical Earth located at the center of a finite universe and surrounded by a concentric rotating sphere in which the stars were embedded. (See Thomas Kuhn’s The Copernican Revolution for a detailed history.) People thought that the stars were very small objects, and thus the outer sphere containing them could be quite nearby.
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