"[Language] allows you to implant a thought from your mind directly into someone else's mind and they can attempt to do the same to you without either of you performing surgery", says Mark Pagel, professor and head of the Evolution Laboratory in the biology department at the University of Reading.
Humans use discrete pulses of sound -- their language -- to alter the internal settings inside someone else's brain to suit an individual's interests. Because language is not a solitary pursuit, language is a form of social learning.
Social learning is visual theft: for example, if I can learn by watching you, I can steal (and benefit from) your best ideas, wisdom or skills without having to invest the time and energy to develop these myself.
There are two options for dealing with this crisis: either retreat into small family groups so the benefits of each group's knowledge are shared only with one's relatives or expand one's group to include unrelated others. Unlike our relatives, the neanderthals, who retreated into small groups, humans chose the second option, and language was the result.
"Language evolved to solve the crisis of visual theft and to exploit cooperation and exchange", says Professor Pagel.
In fact, as Professor Pagel argues, language is a "social technology" that allows for cooperation between unrelated individuals and groups. According to the archaeological record, it was this cooperation and sharing of ideas that preceded human migration around the planet and the ensuing human population explosion.
But almost inexplicably, thousands of languages evolved. So even as a shared language facilitates communication and cooperation between unrelated groups, different languages slow the flow of ideas, technologies -- and even genes.
Can humans afford to have all these different languages, asks Professor Pagel. In a world where we want to promote cooperation, in a world that is more dependent than ever on cooperation to maintain and enhance humanity's levels of prosperity, multiple languages may not be practical.
In fact, humanity's "destiny is to be one world with one language", concludes Professor Pagel.
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I enjoy languages, and I enjoy knowing that there are many thousands of languages spoken on Earth, even if I will never be able to speak nearly all of them. I think that languages reflect the myriad ways that the human mind perceives and responds to the world, and to lose any of them is to (slightly) diminish and limit the variety and expressive depth of human intellectual, creative and experiential capacity.
It might be inevitable that humanity ends up speaking one language (for international commerce?), as Professor Pagel argues, but I argue that there are plenty of reasons why people should actively safeguard the continued existence of all languages, or as many as possible. Just as species need genetic diversity to remain viable, humans need language diversity to remain intellectually and creatively viable. One way to ensure that at least some languages survive is by making sure that everyone on the planet is at least bilingual.
GrrlScientist. 2011. "How language transformed humanity". Guardian. Posted: August 4, 2011. Available online: http://www.guardian.co.uk/science/punctuated-equilibrium/2011/aug/04/1