A disproportionately large number of languages are threatened in places such as northwestern Australia, New Guinea (shown here), northern Eurasia, deserts in Africa and the Middle East, Brazil and northwestern North America, research shows.

Many world languages may become extinct due to economic growth, a new study suggests.

Already today, several of the world's nearly 7,000 languages face a serious risk of extinction. "For example, Ainu, a language in Japan, is now seriously threatened, with only 10 native speakers left," said lead study author Tatsuya Amano at the University of Cambridge in England.

The United Nations has noted that half of the languages spoken today will disappear by the end of this century if nothing is done to save them. "I personally think that the diversity of languages is associated with the diversity of human cultures, which are definitely worth preserving," Amano said.

Amano is a conservation scientist who normally works on species conservation. He became interested in similarities between endangered species and endangered languages.

"Both are seriously threatened, and the distribution of linguistic and biological diversity is very similar," Amano told Live Science. "Of course languages and species are fundamentally different in many aspects, but I thought I might be able to contribute to this urgent problem — language endangerment — using what I have learnt."

Searching for an explanation to the global pattern of language endangerment, Amano and his colleagues first investigated which languages were in danger and, using criteria similar to the ones used for endangered species, determined where those languages were being spoken. Languages were considered endangered if there they were only spoken in a very few places, if few people spoke them and if the number of people who spoke them was rapidly declining. [The Awa: Photos Reveal Faces of a Threatened Tribe]

The scientists found that 25 percent of the world's languages are threatened. After identifying where the endangered languages were, they looked for any environmental and social or economic factors those languages might have in common, such as rugged terrain or rapid population growth.

"We found that at the global scale, language speaker declines are strongly linked to economic growth — that is, declines are particularly occurring in economically developed regions," Amano said.

One important implication of this new study "is that languages in the tropics and Himalayan region are likely to be increasingly threatened in the near future, because these regions still have many local indigenous languages with a small number of speakers, and at the same time are experiencing rapid economic growth," Amano said.

Prior studies in small regions had suggested economic growth and globalization were important drivers of language shifts.

"We showed that this is a global phenomenon, which I think is the most important in our findings," Amano said. "So economically developed countries with many languages, such as the United States and Australia, need immediate attention if their languages are to be conserved."

Economic growth may endanger languages for a variety of reasons. For instance, speakers of endangered languages may view another more dominant language as offering economic opportunities and integration into mainstream society, and thus forego their own languages.

There are other important factors that might endanger languages, the researchers said. For instance, policies regarding how languages are used and taught in schools "can be very different among countries and even within each country, and these factors may explain more detailed patterns in language endangerment," Amano said. "But it was almost impossible to collect such information at the global scale for this study. This will be the next step for our project."

Amano suggested it could be possible to forecast future threats to linguistic diversity. "There exists detailed information on projected future changes in the environment, economies and climates," Amano said. "Using such information, together with the findings of this study and further analysis, we would like to understand what will happen to the world's languages, where it will happen and which languages will be threatened in particular."

Amano also plans on finding out if languages with certain kinds of qualities are particularly threatened with extinction, such as those with complex grammar.

The scientists detailed their findings online Sept. 3 in the journal Proceedings of the Royal Society B.

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