The number of "living" languages spoken in the world is dwindling faster than the decline in the planet's wildlife, according to a new study.
A comparison of the factors affecting the loss of languages and the demise of wild animals has found that the world's 6,000-plus tongues are facing the biggest risk of extinction.
"The threats to birds and mammals are well known but it turns out that languages are far more threatened," said Professor Bill Sutherland, a population biologist at the University of East Anglia in Norwich.
Linguists estimate that there are 6,809 "living" languages in the world today, but 90 per cent of them are spoken by fewer than 100,000 people, and some languages are even rarer – 46 are known to have just one native speaker. "There are 357 languages with under 50 speakers. Rare languages are more likely to show evidence of decline than commoner ones," Professor Sutherland said.
By applying the same principles used to classify the risk to birds and mammals, Professor Sutherland demonstrated that languages were subject to similar forces of extinction.
In the study published in Nature, Professor Sutherland found that the factors that increased the diversity of animal species – notably forest cover, tropical climates and mountainous topography – were also those that influence the richness of local languages. "Countries with large numbers of languages are those with the most forests, are nearer the tropics and with mountain ranges. The same factors affect the number of bird species," he said.
Over the past 500 years, about 4.5 per cent of the total number of described languages have disappeared, compared with 1.3 per cent of birds and 1.9 per cent of mammals. Colonisation has had the strongest influence. Of the 176 living languages spoken by the tribes of North America, 52 have become extinct since 1600. Of the 235 languages spoken by the Aboriginal Australians, 31 have disappeared.
Professor Sutherland said that when comparisons were made to threatened animals, there was a substantially higher proportion of languages that could be considered "critically endangered", "endangered" or "vulnerable" – the three classifications used to describe the threat to birds and mammals. "My extinction risk classification for languages is conservative ... Even with this, it is clear that the risks to languages exceed those to birds and mammals," Professor Sutherland said.
A well-established phenomenon that comes into play when a species declines to small numbers is called the Allee effect – for example when further breeding drops off because animals have difficulty finding a mate. A similar effect may also occur with rare languages. "People just don't want to learn them because they know there are so few others who can speak it," he said. The Leco language of the Bolivian Andes, for instance, is spoken by about 20 people. The Cambap language of Cameroon in Central Africa is used by just 30 native speakers.
Some languages are important because they contain unique characteristics. The Yeli Dnye tongue of the people who live on Rossel Island, in Papua New Guinea, for example, contains unusual sounds and a vocabulary that upsets the universal terminology for describing colours.
Professor Sutherland found that although mountains, forests and the tropics were common factors behind the diversity of animals and languages, both types of extinction did not necessarily occur in the same regions of the world.
Between 200 and 250 languages are spoken by more than a million people, with Chinese Mandarin, English and Spanish being the three most popular tongues.
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