US:One of the world's 7,000 distinct languages disappears every 14 days, an extinction rate exceeding those of birds, mammals and plants, researchers say.
At least 20 per cent of the world's languages are in imminent danger of becoming extinct as their last speakers die off, compared with about 18 per cent of mammals, 8 per cent of plants and 5 per cent of birds.
The extinction of a language translates into a loss of knowledge, said linguist David Harrison, associate director of the Living Tongues Institute and a linguist at Swarthmore College in Pennsylvania.
"When we lose a language, we lose centuries of thinking about time, seasons, sea creatures, reindeer, edible flowers, mathematics, landscapes, myths, music, the unknown and the everyday."
Half the world's languages have disappeared in the past 500 years, and half of the remainder are likely to vanish this century, Harrison said.
Many of the languages are not translated easily into English. In the endangered south Siberian language Todzhu, for example, the word chary means "five-year-old male castrated reindeer that can be used for riding".
Harrison and Living Tongues director Gregory Anderson have identified five language "hot spots" where the extinction rate is particularly high, they said at a news conference on Tuesday sponsored by the National Geographic Society, which is supporting their research.
One such area encompasses Oklahoma, Texas and New Mexico, where 40 languages spoken by American Indians are at risk. Only five elderly members of the Yuchi tribe, for example, are fluent in the Yuchi language, which might be unrelated to any other language.
The top "hot spot" is northern Australia, where 153 languages spoken by aborigines are at risk. There are three known speakers of Magati Ke in the Northern Territory, and three Yawuru speakers. The team found one elderly speaker of Amurdag - which previously had been declared extinct - and he barely could recall the language spoken by his father.
Other "hot spots" include central South America, parts of the Pacific northwest and eastern Siberia. All the areas are similar in that they were successfully colonised, with indigenous languages giving way to a colonial language, either voluntarily or through coercion.
Researchers from the institute are visiting these locales and using digital audio and video equipment to record the last speakers of the most endangered tongues. "In many cases, these are the first and only digital recordings of the languages," Anderson said.
In as few as seven to 10 days, they can record enough information to prevent the complete loss of a language, he said.