The decline of linguistic and cultural diversity is linked to the loss of biodiversity, a study has suggested.
The authors said that 70% of the world's languages were found within the planet's biodiversity hotspots.
Data showed that as these important environmental areas were degraded over time, cultures and languages in the area were also being lost.
The results of the study have been published in the Proceedings of the National Academy of Sciences (PNAS).
"Biologists estimate annual loss of species at 1,000 times or more greater than historic rates, and linguists predict that 50-90% of the world's languages will disappear by the end of the century," the researchers wrote.
Lead author Larry Gorenflo from Penn State University, in the US, said previous studies had identified a geographical connection between the two, but did not offer the level of detail required.
Dr Gorenflo told BBC News that the limitation to the data was that either the languages were listed by country or there was a dot on the map to indicate the location.
"But what you did not know was if the area extended two kilometres or 200 kilometres, so you really did not get a sense of the extent of the language," he explained.
"We used improved language data to really get a more solid sense of how languages and biodiversity co-occurred and an understanding of how geographically extensive the language was."
He said the study achieved this by also looking at smaller areas with high biodiversity, such as national parks or other protected habitats.
"When we did that, not only did we get a sense of co-occurrence at a regional scale, but we also got a sense that co-occurrence was found at a much finer scale," he said.
"We are not quite sure yet why this happens, but in a lot of cases it may well be that biodiversity evolved as part-and-parcel of cultural diversity, and vice versa."
In their paper, the researchers pointed out that, out of the 6,900 or more languages spoken on Earth, more than 4,800 occurred in regions containing high biodiversity.
Dr Gorenflo described these locations as "very important landscapes" which were "getting fewer and fewer" but added that the study's data could help provide long-term security.
"It provides a wonderful opportunity to integrate conservation efforts - you can have people who can get funding for biological conservation, and they can collaborate with people who can get funding for linguistic or cultural conservation," he suggested.
"In the past, it was hard to get biologists to look at people.
"That has really changed dramatically in the past few years. One thing that a lot of biologists and ecologists are now seeing is that people are part of these ecosystems."