Biology Magazine

When Did Language Evolve?

Posted on the 27 May 2014 by Reprieve @EvoAnth

Language is one of our most unique and important attributes. No other form of animal communication comes close to conveying the sheer amount of information we can. As such language has understandably attracted a lot of attention from scientists trying to figure out when, why  and how it evolved. Unfortunately for them (and us regular folk interested in what they find out) very little evidence of language is preserved for any length of time. The brain responsible for understanding it rots away, as does the the tongue and lips which generate the noises. Given this paucity of evidence, how far back can we trace the emergence of language?

Some of the oldest known writing, from Jemdet Nasr

Some of the oldest known writing, from Jemdet Nasr

The most obvious place to start looking is when words do leave behind physical evidence, as they are doing right now. The written word! Alas the oldest evidence of writing only goes back a mere 6,000 years; with the “proto-writing” from which it emerged only a few thousand years older1. Although this might seem like a long time, being older than most civilisations, our family diverged from the other apes more than 7 million years ago. Put in that context it doesn’t seem that impressive.

Art and ornamentation might be able to shift it back further. Our ancestors were creating beautiful paintings on cave walls 40,000 years ago and making beaded necklaces almost a hundred thousand years before that; making it orders of magnitude older than writing. Although not explicitly language-based (these aren’t hieroglyphs), this art appears to convey complex information about tribal identity and more; prompting many to conclude that it’s makers must have had language in order to understand it2.

This raises some fascinating possibilities since our close cousins, the Neanderthals, also made this sort of beaded jewellery3. Could it mean that they were also capable of language just like us? To try and figure out the answer, one way or the other, people began looking for other evidence of language. Some genes have been found that appear to be linked to language, the most famous of which being FOXP2. And this gene does seem to be present in Neanderthals. However, other, less well known (yet also important) genes are missing from the Neanderthals4. Perhaps then, they could speak but it wasn’t quite on par with our language?

A Neanderthal skull and hyoid bone (shown beneath the skull)

A Neanderthal skull and hyoid bone (shown beneath the skull)

So people began looking at the hyoid bone. This tiny bone in the neck provides an anchor for the tongue and other muscles needed for speech, allowing us to make the range of noises needed for language. And the Neanderthals have one that is effectively indistinguishable from ours5; lending further credibility to the idea that they were capable of at least some sort of speech. This bone isn’t direct evidence of language, with grammar and syntax and all that fun stuff, but the fact that evolution was selecting for anatomy that made the myriad of noises needed for speech possible strongly suggests they were actually speaking. It may not have been fully modern, but was likely leaps and bounds above other animal communication. What’s more it raises the possibility that language is even older. After all, if humans and Neanderthals both have the modern version of this bone, then perhaps the ancestor we both evolved from – Homo heidelbergensis - also had it.

Atapuerca is a Spanish site that covers almost a million years of prehistory. One cave in this system, Sima de los Huesos, appears to be a natural trap; with a long drop for an utterance that many animals fell into and died, including several H. heidelbegensis. What’s more, since no predators made it to the bottom these corpses remained undisturbed, so the fragile hyoid bone was able to survive in a couple of cases. And sure enough, these also seem similar to the modern human bone; again providing evidence of language up to 500,000 years ago6: more than twice the age of Homo sapiens.

But just how far back can the hyoid bone take us? As I said, it’s so tiny that it often gets destroyed so we only have a handful of earlier examples. Homo erectus, the ancestor of H. heidelbergensis, seems to have a hyoid bone intermediary between us and earlier, more ape like species7. As such there’s little reason to think that they could talk. But the fact it does appear to be in the process of evolving is interesting, suggesting that language was beginning to evolve. H. erectus also had a much bigger brain than earlier species. Perhaps they were using it to develop a greater range of calls that could convey more information; driving the evolution of the hyoid bone to allow them to make a greater variety of calls.

Other lines of evidence appear to fit within this pattern. Atapuerca also contains the skulls of many H. heidelbergensis, preserving their ear canal8. Unlike chimps, this is tuned to best hear the pitch at which humans talk; but there’s little evidence of such tuning in Homo erectus. Attempts to reverse engineer the evolution of language suggest it evolved ~500,000 years ago; in the time of H. heidelbergensis. But then, there are a few facts that seem to contradict this story. Simulations of the effect of group size on language suggest that Homo erectus may have had to have had language; and imprints of their brain show some of the regions associated with language – Wernicke’s area and Broca’s area – were very pronounced9.

Broca's area in chimps.

Broca’s area in chimps.

But the researcher responsible for the simulation has backed off a bit, suggesting instead that it simply implies they had a sort of proto-language. And those regions of the brain are also pronounced in chimps, who, as you may have noticed, don’t talk. Granted they’re more pronounced in H. erectus, but perhaps this would be consistent with a proto-language. Taken all together this evidence seems to suggest that Homo erectus marks the beginning of the evolution of language, but it did not fully develop into something we would recognize as language until Homo heidelbergensis. Even then, there’s debate over just how similar their speech would’ve been to ours. After all, the hyoid bone is not direct proof of language and the Neanderthals (descendants of this species) are missing several key genes.

When did language evolve? Well after a thousand pages of waffling it seems there’s no definitive answer. There’s strong evidence it arose in the time of H. heidelbergensis, 500,000 years ago, having begun earlier with H. erectus, almost 2 million years ago. But without more evidence it’s unlikely we’ll settle the issue for a while. It’s enough to make you wish we’d never invented the damn thing so we could avoid all this confusion. One thing that does seem apparent though is that it probably isn’t unique to us. Neanderthals and our ancestors all have enough evidence to suggest they had some capacity for language, even if it wasn’t fully modern. I’d love to have been alive when they were to see what talking to them would be like.

Okay, I probably wouldn’t love it that much. What with all the death, predators and having to fight a mammoth for your meal. Maybe clone a Neanderthal so I can speak to him without having to watch out for sabre tooth tigers.

References

  1. Scarre, C. (2005). The human past: world prehistory and the development of human societies. Thames & Hudson.
  2. d’Errico, F., Henshilwood, C., Vanhaeren, M., & Van Niekerk, K. (2005). < i> Nassarius kraussianus</i> shell beads from Blombos Cave: evidence for symbolic behavior in the Middle Stone Age. Journal of human evolution48(1), 3-24.
  3. Zilhao, J. (2012). Personal ornaments and symbolism among the Neanderthals.Developments in Quaternary Science16, 35-49.
  4. Berwick, R. C., Hauser, M. D., & Tattersall, I. (2013). Neanderthal language? Just-so stories take center stage. Frontiers in psychology4
  5. D’Anastasio, R., Wroe, S., Tuniz, C., Mancini, L., Cesana, D. T., Dreossi, D., … & Capasso, L. (2013). Micro-Biomechanics of the Kebara 2 Hyoid and Its Implications for Speech in Neanderthals. PloS one8(12), e82261.
  6. Martínez, I., Arsuaga, J. L., Quam, R., Carretero, J. M., Gracia, A., & Rodríguez, L. (2008). Human hyoid bones from the middle Pleistocene site of the Sima de los Huesos (Sierra de Atapuerca, Spain). Journal of human evolution54(1), 118-124.
  7. Capasso, L., Michetti, E., & D’Anastasio, R. (2008). A Homo erectus hyoid bone: possible implications for the origin of the human capability for speech.Collegium antropologicum32(4), 1007-1011.
  8. Martínez, I., Rosa, M., Arsuaga, J. L., Jarabo, P., Quam, R., Lorenzo, C., … & Carbonell, E. (2004). Auditory capacities in Middle Pleistocene humans from the Sierra de Atapuerca in Spain. Proceedings of the National Academy of Sciences of the United States of America101(27), 9976-9981.
  9. Cunningham, D. L. (1999). Language and human evolution.

Back to Featured Articles on Logo Paperblog

Magazines