Islands are engines of linguistic diversity, study shows

Islands drive language change and generate language diversity in similar ways to how they drive species diversity, according to research from The Australian National University (ANU) that analyzed languages from over 13,000 inhabited islands. The research is published in Nature Ecology & Evolution.

Although accounting for a tiny proportion of the world's land mass, islands have had a disproportionately large impact on biological science because they show evolution in action.

One example of this is the Galapagos Islands, famous for shaping 19th-century naturalist Charles Darwin's thoughts on evolution.

ANU biologists were interested in whether islands played a similar role in understanding language change and diversity. They developed a database of all languages from over 13,000 inhabited islands to answer this question.

Study lead author and ANU evolutionary biologist, Professor Lindell Bromham, said that nearly a fifth of the world's languages are spoken on islands, despite islands representing less than 1% of the world's land mass.

"Islands are evolution's laboratories. To Darwin, islands were a microcosm of the processes of change that occurred everywhere," she said.

"We were curious why islands capture so much of the world's linguistic diversity. When we analyzed the global database, we found that islands play a similar role in generating language diversity as they do for biodiversity."

According to the ANU researchers, the number of island endemic languages increases with both island size and distance from the mainland.

"Around 10% of languages are endemic to islands, used only, or predominantly, on islands," Professor Bromham said.

"Island languages also show distinct patterns of evolution, with languages spoken predominantly on islands having significantly fewer phonemes, the basic sound units from which words are made."

The research builds on earlier studies that looked at global patterns of language diversity and endangerment. The earlier study found that global linguistic diversity is undergoing a crisis of loss that is as severe as the threat to biodiversity, with over a third of the world's languages endangered, and potentially 1,500 languages lost by the end of the century.

"Our analysis shows that island endemic languages do not have significantly higher levels of endangerment than their mainland counterparts," Professor Bromham said.

"But because islands hold such a disproportionately large share of global language diversity, they will play a crucial role in safeguarding linguistic diversity.

"Islands are not only cradles of linguistic diversity but also arks carrying language diversity forward into the future."