One of the world's 7,000 distinct languages disappears every 14 days, an extinction rate exceeding that of birds, mammals or plants, researchers said Tuesday.
At least 20% of the world's languages are in imminent danger of becoming extinct as their last speakers die off, compared with about 18% of mammals, 8% of plants and 5% of birds.
The extinction of a language translates into a loss of knowledge, said K. David Harrison, associate director of the Living Tongues Institute for Endangered Languages and a linguist at Swarthmore College.
"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," he said.
Half of the world's languages have disappeared in the last 500 years, and half of the remainder are likely to vanish during this century, Harrison said.
Many of the languages are not easily translated into English. In the endangered south Siberian language Todzhu, for example, the word "chary" means "2-year-old male castrated reindeer that can be used for riding."
Harrison and Living Tongues Director Gregory D.S. Anderson have identified five language "hot spots" where the extinction rate is particularly high, they said at a news conference sponsored by the National Geographic Society, which supports their research.
One such area encompasses Oklahoma, Texas and New Mexico, where 40 languages spoken by Native Americans are at risk. Only five elderly members of the Yuchi tribe, for example, are fluent in the Yuchi language, which may be unrelated to any other language in the world.
The top hot spot is northern Australia, where 153 languages spoken by Aborigines are at risk. There are currently only three known speakers of Magati Ke in the Northern Territory and three Yawuru speakers. The team found one elderly speaker of Amurdag -- which had previously been declared extinct -- and he could barely 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 colonized with indigenous languages giving way to a colonial language either voluntarily or through coercion. A map of the hot spots is at www.languagehotspots.org.
The Native American languages in Oklahoma are giving way to English, Anderson said. That process has already taken place on the East Coast, which was colonized earlier. Virtually all indigenous languages have disappeared there.
Researchers from the Living Tongues 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.