This highlights an intriguing paradox at the heart of human communication. If language evolved to allow us to exchange information, how come most people cannot understand what most other people are saying? This perennial question was famously addressed in the Old Testament story of the Tower of Babel, which tells of how humans developed the conceit that they could use their shared language to cooperate in the building of a tower that would take them to heaven. God, angered at this attempt to usurp his power, destroyed the tower and to ensure it would not be rebuilt he scattered the people and confused them by giving them different languages. The myth leads to the amusing irony that our separate languages exist to prevent us from communicating. The surprise is that this might not be far from the truth. [. . .]
Of course that still leaves the question of why people would want to form into so many distinct groups. For the myriad biological species in the tropics, there are advantages to being different because it allows each to adapt to its own ecological niche. But humans all occupy the same niche, and splitting into distinct cultural and linguistic groups actually brings disadvantages, such as slowing the movement of ideas, technologies and people. It also makes societies more vulnerable to risks and plain bad luck. So why not have one large group with a shared language?
An answer to this question is emerging with the realisation that human history has been characterised by continual battles. Ever since our ancestors walked out of Africa, beginning around 60,000 years ago, people have been in conflict over territory and resources. In my book Wired for Culture (Norton/Penguin, 2012) I describe how, as a consequence, we have acquired a suite of traits that help our own particular group to outcompete the others. Two traits that stand out are "groupishness" - affiliating with people with whom you share a distinct identity - and xenophobia, demonising those outside your group and holding parochial views towards them. In this context, languages act as powerful social anchors of our tribal identity. How we speak is a continual auditory reminder of who we are and, equally as important, who we are not. Anyone who can speak your particular dialect is a walking, talking advertisement for the values and cultural history you share. What's more, where different groups live in close proximity, distinct languages are an effective way to prevent eavesdropping or the loss of important information to a competitor.
In support of this idea, I have found anthropological accounts of tribes deciding to change their language, with immediate effect, for no other reason than to distinguish themselves from neighbouring groups. For example, a group of Selepet speakers in Papua New Guinea changed its word for "no" from bia to bune to be distinct from other Selepet speakers in a nearby village. Another group reversed all its masculine and feminine nouns - the word for he became she, man became woman, mother became father, and so on. One can only sympathise with anyone who had been away hunting for a few days when the changes occurred.
The use of language as identity is not confined to Papua New Guinea. People everywhere use language to monitor who is a member of their "tribe". We have an acute, and sometimes obsessive, awareness of how those around us speak, and we continually adapt language to mark out our particular group from others. In a striking parallel to the Selepet examples, many of the peculiar spellings that differentiate American English from British - such as the tendency to drop the "u" in words like colour - arose almost overnight when Noah Webster produced the first American Dictionary of the English Language at the start of the 19th century. He insisted that: "As an independent nation, our honor [sic] requires us to have a system of our own, in language as well as government."
War of words: The language paradox explained
New Scientist article (free copy) by Mark Pagel (via Jason Malloy's bookmarks). Some mostly worthwhile paragraphs precede the requisite pollyannaish-on-globalism denouement.