Image copyright Thinkstock Image caption The better the economy, the more likely a national language will dominate

Economic development is driving the extinction of some languages, scientists believe.

A study has found that minority languages in the most developed parts of the world, including North America, Europe and Australia, are most at threat.

The research is published in the Proceedings of the Royal Society B.

The researchers say that efforts to protect these languages need to be focused on these areas.

Lead author Tatsuya Amano, from the University of Cambridge, said: "World languages are now rapidly being lost. This is a very serious situation.

"We wanted to know how the extinction is distributed globally and what are the main drivers of this."

Vanishing voices

Dr Amano, who usually looks at extinction rates in animals, said that about 25% of languages around the world were under threat.

People are forced to adopt the dominant language or risk being left out in the cold - economically and politically Tatsuya Amano, University of Cambridge

The researchers found that the more successful a country was economically, the more rapidly its languages were being lost.

They said that in North America, languages such as Upper Tanana, were now spoken by fewer than 25 people in Alaska, and were at risk of vanishing forever.

In Europe, languages such as Ume Sami in Scandinavia or Auvergnat in France are fading fast.

Dr Amano said: "As economies develop, one language often comes to dominate a nation's political and educational spheres.

"People are forced to adopt the dominant language or risk being left out in the cold - economically and politically."

The team also found that languages in the Himalayas are at risk, such as Bahing in Nepal, which has an estimated eight speakers. In the tropics, too, voices are disappearing.

"These countries are experiencing rapid economic growth, so in the near future these languages will face risk of extinction."

The scientists call for conservation efforts to focus on these regions.

Dr Amano said that work undertaken to protect languages such as Welsh in the UK was a good example a successful strategy.

Commenting on the research Daniel Kaufman, executive director of the Endangered Language Alliance, said: "Environmental factors have been overshadowed by social, political and economic factors.

"We are now seeing a pattern of linguistic diversity that was originally shaped by the environment give way to a pattern that is being shaped by policy and economic realities.

"The environmental pattern at this point is largely historical residue. That is, we will no longer see areas of a particular environmental type attract or spawn language diversity. The economic aspect, however, cannot be overemphasized, as there are places within the language diversity 'hotspots' where whole villages are being emptied out due to out-migration.

"Because much of this migration is recent and undocumented, accurate numbers are unfortunately not readily available for statistical analysis."

Follow Rebecca on Twitter