The Language Gene
What are two things that humans consciously do more than any other?
I am willing to wager that speaking and listening are high on the list; and that of all the milestones in our history, stretching as far back as humans have existed, language development was probably the most significant.
We are only now, thousands of years later, beginning to get an inkling of the magnitude and significance of that event, yet the origin of language—how it developed as a capability and what caused it to appear in Homo sapiens—has no simple answer. Whether it happened gradually, or through discontinuous change, it is impossible to say.
Language origin has been a contentious subject. In 1866 the Linguistic Society of Paris published an edict banning origin of language discussions as none had a scientific basis and arguments were prolonged and heated.
With the acceptance of the theory of evolution, some advocate that language sprang up when humans acquired a more sophisticated brain that made language learning and invention possible.
Others believe that language is more a cultural phenomenon than one dictated solely by genetics, and that language ability and usage has grown in step with advances in social interaction.
Some suggest that this process took place over a protracted period and that language is so complex, it is hard to conceive that it appeared from nothing. It must have evolved slowly somewhere among our prehuman ancestors.
Then there is the view that language sprang up suddenly as an emergent phenomena, independent of any external event.1
The leading advocate of this latter approach called “the discontinuity theory of language” is Noam Chomsky. He posits that a chance mutation occurred in one individual about 100,000 years ago, and that mutation triggered the emergence of language capability that spread to succeeding generations. One moment there was no human innate ability for language and the next, there was. The change was small but ultimately monumental because it was so unique.
There are properties of our language-making ability that have no analog in any other species or even elsewhere in our own minds. One such property is that there are no fractional words. Words come in whole sizes just like bits of digital information that are marked as a 0 or a 1, on or off. There are no fractions.
Secondly, there is no upper limit to the number of words that can be strung together in a sentence. It is infinite. It is as if our minds in this area have no limit.
The only similarity is found in arithmetic and numbers which very well might be a product of the same language-making ability.2
One of the arguments counter to Chomsky’s development of a language facility through evolution is that it is difficult to envisage how starting with only one mutation, all humans now have the same language facility without exception. How many generations would be required to see this type of saturation, and how much time would be needed? Would that be enough time? The concept of widespread and rapid distribution of a beneficial genetic mutation is called “selective sweep” and has happened occasionally but only rarely in human adaptation.
Research into the human genome and the results of gene sequencing and mapping are beginning to shed some light on this area of language, particularly as regards to a gene named FOXP2.
This gene became the focus of attention starting in 1990. Its significance surfaced when a particular family (of some thirty individuals over three generations) was studied as a result of a shared speech and language difficulty. Half suffered a speech deficiency and half did not. The difference between the two was isolated to damage in the FOXP2 gene.
A gene is a small part of a DNA strand that is linked to a specific feature of a species, such as determining eye color. Not all genes act in the same way. Some directly produce a specific characteristic while others act indirectly by manufacturing proteins that turn on some genes and turn off others like a switch. The FOXP2 gene is a member of the latter class. The significance of this type of gene is that it can create widespread effects as a body develops.
At the time of its discovery and isolation as an influence on language and speech ability, it was hailed as “the language gene”. Since that time, more research has been done and it has been found that the FOXP2 is fairly widespread throughout the animal kingdom, and not exclusive to Homo sapiens. This seems to indicate that language ability is also found elsewhere in the animal world.
Chimpanzees and other apes have a FOXP2 gene that differs in only two of the 715 amino acids that make up the gene in humans.
All bird species have a similar version of FOXP2. Research in mice and birds has found that the FOXP2 not only affects vocalization but the ability to learn and the development of the brain.
The FOXP2 was also found to have existed in Neanderthals, and it was discovered that they had the same two mutations carried by Homo sapiens when the human line split from chimpanzees some 5-6 million years ago, posing the question of whether they too were capable of spoken language. We do not know. There may be other genes involved in our own development that we currently do not know about that further differentiate our language ability from other genetic lines.
Comparisons of gene sequences with other species had put the origins of the Human FOXP2 between 100,000 and 200,000 years ago. The Neanderthal human split came around 400,000 years ago so the Neanderthal DNA seems to suggest the emergence of this gene was earlier than thought, but the mutated gene only became widespread and uniform later in humankind’s history.3
Whether language acquisition as an ability arose rapidly in just the last the 100,000 years, or as a much lengthier development is still not pinned down, but it is certain that genetic research will continue to shed further light as more is discovered.
1 Crystal, D. (2005). The Origins of Language. In The Cambridge Encyclopedia of Language, Second Edition. Cambridge, UK: Cambridge University Press.
2 Chomsky, N. (2000). The ‘Chomskyan Era’ excerpted from “The Architecture of Language” . Retrieved March 19, 2012, from http://www.chomsky.info/books/architecture01.htm
3 Yong, E. (2009, November 11). Revisiting FOXP2 and the Origins of Language. Retrieved March 19, 2012, from http://scienceblogs.com/notrocketscience/2009/11/11/revisiting-foxp2-and-the-origins-of-language/
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