Of the 7,000 languages spoken in the world today, linguists   say, nearly half are likely to disappear this century. In fact, one falls out of use about every two weeks. Some languages die out in an instant, at the death of the only surviving speaker. Others are lost gradually in bilingual   cultures, as local tongues are edged out by the dominant   language at school, in the marketplace and on television. New research, supported by the National Geographic Society and the Living Tongues Institute for Endangered Languages, has found the five regions where languages are disappearing most rapidly. They are northern Australia, central South America, North America's upper Pacific coastal zone, eastern Siberia, and Oklahoma and the southwestern United States. K. David Harrison, an associate professor of linguistics at Swarthmore College, US, said that more than half the languages had no written form and were _ to loss and being forgotten." Their loss leaves no dictionary, no text, or no record of the accumulated knowledge and history of a disappeared culture. Harrison and other researchers started their rescue project last year. They have been trying to identify and record endangered languages. They interviewed and made recordings of the few remaining speakers of a language and collected basic word lists. The individual projects, some lasting three to four years, involve hundreds of hours of recording speech, developing grammar and preparing children's readers in the obscure   language. The research has concentrated on preserving entire language families. "These are probably languages that cannot be brought back, but at least we made records of them," said Gregory Anderson, director of the Living Tongues Institute, in Oregon, US. One of the things that Harrison and other researchers did was  _  .
to have more people speak the disappearing language to make records of the disappearing language to limit dominant languages to publish a dictionary of the disappearing language