In 2018, when Soner Oruç and Ceren Kazancı visited the Caucasus, a mountainous region between the Black and Caspian Seas, a local plant called kurum was nearly impossible to find. In the 1970s, kurum, a grass topped with a flowering head of millet-like seeds, had been a major food source for the Laz people, one of the indigenous groups that live there, near the border of Turkey and Georgia. But today, kurum can only be chanced upon as an occasional birdseed.

The plant took something unexpected with it into oblivion: the native words used to describe it. “Its role as food for people has been erased from the land, along with the memories of which plant species are related to it, the process of its cultivation and harvest, and the bread, soup, rice, and other traditional dishes associated with it," Oruç, an ornithologist, and Kazancı, a PhD student, wrote . "Unfortunately, all the local words related to this information have sunk without a trace.”

As we face a potential emergency in biodiversity loss from human activity and human-caused climate change, these complex interactions of language and biodiversity are a reminder that our cultural lives are wrapped up in the natural world too. Just like an animal species, our languages evolved in the context of the environments that surrounded them. When we change those environments, we threaten much more than just the physical living things that thrive there.

The habitat losses that affect species can affect indigenous people, changing their relationship with the land—and by extension, the language they use—or forcing them to relocate to places where they have to stop speaking their native tongues. Influxes of foreigners and industry can also lead people to prioritize other languages, even while remaining in the same place. In some cases, the damages to cultural and linguistic diversity seems to come first, and ripple out into the environment through an abandonment of indigenous knowledge and care of local ecosystems.

The loss of kurum reveals that another casualty of biodiversity loss is language. Since the 1990s, scientists have noticed that areas with high levels of biodiversity are also home to many different languages. When those areas face a loss of plant and animal species, there can be similar extinctions in words, phrases, or even entire languages.

The World Wildlife Fund (WWF) describes the Caucasus as " one of the world’s biologically richest yet most threatened areas ." It contains more than twice the animal diversity found in neighboring lands, but its biodiversity—the variety of plant and animal life in an ecosystem—is rapidly disappearing, due to human activities. In this regard, the Caucasus is not unique. Earlier this year, a United Nations (UN) report on global biodiversity found that humans have put as many as 1 million other species at risk of extinction, by altering or destroying three-quarters of the world’s land environments, two-thirds of its marine habitats, and 85 percent of the most important wetland regions.

A more recent study in PNAS confirmed that regions that have high levels of biodiversity also contain a vast amount of the world's linguistic diversity: Of the nearly 7,000 languages on Earth, more than 4,800 of them are spoken in those areas of high biological diversity. This means that almost 70 percent of languages are spoken on about 25 percent of the Earth’s surface—the very same areas where species are concentrated.

Terralingua helped to create the Index of Linguistic Diversity, a measurement of the world’s languages. Between 1970 and 2005 , research found, linguistic diversity had dropped by 20 percent. In response to Maffi's larger gut feeling, Terralingua also made maps that showed the overlap of biodiversity and linguistic diversity and compared the losses . The two were closely tracking each other. Maffi helped coin the phrase " biocultural diversity ," a nod to the fact that biological, linguistic, and cultural diversity tend to converge in the same areas.

“I had an intuition that all those phenomena of diversity loss had to be connected,” said Maffi, now the director of Terralingua , a non-profit she co-founded focused on diversity in nature and culture. "I saw biodiversity, cultural diversity, and linguistic diversity as distinct but interrelated manifestations of the diversity of life on earth, and thought that there must be common causes and consequences of the loss of each of them.”

In the mid-1990s , right around the time that biologists and conservationists were sounding an alarm about global biodiversity loss, linguists and anthropologists were also expressing concern about losses in the world's cultures and languages. Luisa Maffi, a researcher with a background in linguistics, anthropology, and natural sciences, felt it wasn't a coincidence.

Unlike a species extinction, a language isn’t necessarily lost because all the people who speak it die. It’s usually because a population is forced to live in a different context and stops speaking it, sometimes by force.

“As a biologist, I see this process very much like, or parallel to, the situation with invasive species, which might get taken from one part of the world to another and then the indigenous species start to disappear because of competition, predation, or disease spreading,” Loh said.

Most of the world's languages are already spoken by very small numbers of people. About half of the world's population speaks one of 24 of the "big" languages, like English, Spanish, Mandarin, Russian, Hindi, and Arabic, said Jonathan Loh, an honorary research associate at the University of Kent in the School of Anthropology and Conservation, who previously helped produce The Living Planet Report for WWF, an annual report on the state of the planet’s biodiversity.

Many of those languages are facing extinction, just like the species that live there. Linguists estimate that 50 to 90 percent of the world’s languages will disappear by the end of the century, and four in 10 indigenous languages are at risk of disappearing, according to UN human rights experts. Around 2,800 of the languages that are in these areas of high biodiversity are endangered—they have 10,000 or fewer speakers. More than 1,200 of those languages have 1,000 or fewer speakers.

Loh thinks of languages as their own kinds of species that interact with the natural environments around them. They develop, evolve, and depend on the animals and plants that live there. Family trees can be sketched out for languages, just like they can be for animal species. Once they're removed from those environments, they begin to fade.

Species like the Yosemite woolly sunflower, a small yellow flower in the daisy family, and Tompkin’s sedge plant, a native grass, started to die from lack of sunlight and competition with other species. Populations of animal species, like the Sierra Nevada red fox, also began to shrink. This biodiversity loss mirrored a plummeting in the health of native language, as The Revelator pointed out: Today, only 400 people speak the Northern Paiute language spoken in Yosemite, and only three speak Southern Sierra Miwok .

“The Miwoks’ and Paiutes’ careful husbandry over millennia, supported by the languages that detailed techniques and terrain with no direct English translation, fell into disrepair after the people were forced out of the valley,” reported The Revelator , the Center for Biological Diversity’s publication. "The open groves of oak, willow and sedge gave way to crowded stands of coniferous forests, which grew rank with dead needles, grass and undergrowth."

John Muir, a naturalist and the so-called "Father of National Parks," was awed by the beauty he saw in Yosemite Valley, but he didn't realize that it was in large part due to Native American cultivation. Forty years after the indigenous people were gone from Yosemite, the state guardian of the Yosemite Grant found that almost all of Yosemite's meadowland had disappeared. The Native Americans used fire to routinely clear the valley, and those fires contributed to its biodiversity; a 1996 report by the Sierra Nevada Ecosystem Project wrote that many of the native plants in Yosemite are shade-intolerant—the fires removed large trees that had prevented those plants from growing, and "the result was that plant diversity was maximized."

In what's now Yosemite National Park, indigenous people called Paiutes and Miwoks once lived on and managed the land for crops and livestock. The U.S. government drove Native Americans out of their lands during the creation of national parks, and when the indigenous people of Yosemite Valley left, so ended the interaction of their indigenous cultural practices with that environment.

In the Eastern base of the Central Peruvian Andes, the Amuesha tribe has a long history of growing different kinds of cassava, a root vegetable; elevation and topography changes how it's grown, what pests try to eat it, and how big or what color it might be—in one study , up to 700 varieties of cassava were named.

When a language is lost, it’s not just the words and grammar that go—many other aspects of the culture start to disappear. Indigenous cultures are rich with ecological and environmental knowledge—facts about different plants, animals, and ecosystems are bound up together with language.

“There’s a lot of the natural habitat that indigenous people, who were speakers of indigenous languages, would have relied upon that isn’t there anymore,” Gorenflo said. “So they’ve moved away, or in some cases, they’ve converted in a sense—become more westernized and in the process have lost languages.”

He recounted one of many contemporary examples: Soybean agriculture is currently encroaching on a Brazillian grassland area called the Cerrado , where there are 216 Indigenous territories and 83 different ethnic groups, as well as more than 4,800 species that aren't found anywhere else in the world. The conversion of this area into agricultural land has led to deforestation , an influx of farmers, and disruption to local ecosystems—all devastating ongoing losses in biocultural diversity.

Most natural habitats today are lost, not to natural parks, but to agricultural production or resource extraction, said Larry Gorenflo, a geographer and professor at Penn State University and the first author of the PNAS paper .

All of this native knowledge, packaged into cultural practices and language, encouraged an appreciation and understanding of cassava diversity. Once the language started to dissipate, so did the skills and abilities to grow cassava—a cultural blow that ultimately led to fewer varieties of cassava. Cassava is grown now mostly for mainstream markets, where "the variety of cassava did not matter, only the production."

It was considered a woman's crop, and the cassava field was such a protected place that even daughters had to ask permission to enter their mother's fields. Women sang the "Song for Cultivation" to the growing cassava: "__You are happy now that we are cultivating you.”

An Amuesha myth says that before the beginning of this world, cassava roots were humans, and at the end of the world, they would become human again. That led to culturally high stakes for cassava cultivation, and informed how attentively and tenderly cassava was grown—the fields had to be organized, because the legend said that cassava were neat and fastidious when they were people.

The Amuesha are severely endangered, and a study found that the “loss of speakers and knowledge-keepers among the Amuesha has directly and negatively impacted the diversity" of cassava. The names and knowledge around cassava types were rooted in traditional songs, colors, or paired with terminology of other local plants and animals.

By studying and revitalizing ancestral sayings of the Maori people of New Zealand, new information was found about growing plants, soils and nutrients, and the landscape. In a separate analysis of satellite data , researchers found that indigenous lands could serve as barriers to deforestation.

These narratives raise an intriguing possibility, Maffi said. If there is a causal link between biodiversity and culture, perhaps preserving culture can act as a form of ecological conservation as well.

“Being removed from their lands and from their ways of life, and having alien cultures and languages imposed on them, would make it essentially impossible for local people to continue to care for the natural environment the way they used to," Maffi said. "In the meantime, the settlers, not guided and restrained by those same values, would often indiscriminately exploit the land and its resources, triggering environmental degradation.”

In this regard, Maffi views the presence of language and biodiversity in a place not just as an association, but as as two interrelated factors that rely on each other. If the natural environment becomes dysfunctional and leads to biodiversity loss, it can affect the loss of culture and language. But she sees cases where cultural and linguistic shifts come first, like with cassava, and then environmental degradation follows.

In a 2012 study in the South African Journal of Science, the authors evaluated the cultural significance of the thicket, and found ties between use of the traditional language and the land. “I like going to the forest with my friends and mom to collect firewood," a 15-year-old girl said. "We gossip and my mom teaches me the names of trees and I teach my friends. I feel happy when I'm in the forest." A 30-year-old man said, "I am showing my 3-year-old son traditional medicines from the forest. It is important that he knows these things [because] it is part of being Xhosa!"

The Xhosa's deep connection to the forest "has permeated the Xhosa language, imbuing idioms, proverbs, riddles, names of months and times of day, stories, legends, songs, chants, and more," according to a Terralingua profile on the group.

The Albany Thicket, also known as the “Xhosa forest," is a critical and endangered ecosystem that has long-standing cultural ties with the Xhosa, an indigenous group located mainly in the Eastern and Western Cape provinces of South Africa.

It's one potential way to use this association for good: if efforts to preserve cultural and indigenous diversity and language can feed back into overall biodiversity, it might be possible as a strategy to preserve both.

In Hawaii, populations of green sea turtles, or honus, declined alongside the Hawaiian language, which was banned from public schools in 1896. But in the 1970s and 80s, there were widespread efforts to introduce the culture and language to the people. “As Hawaiian has made a comeback since the 1980s, so has the honu’s nesting rate —a 53 percent increase over the past 25 years,” The Revelator wrote in 2018 about about the correlation.

A person in Montana or Ottawa may never see the Xhosa forest, so how crucial is it to them, to preserve those words that describe it? Loh said this is a perspective he hears in the context of biodiversity loss too: If a rare plant or animal disappears on the other side of the world, does it really matter? It can feel even more abstract when it comes to language.

Loh said there's a couple of reasons to care. One is based on principle: We could care because once a species is gone, it’s likely gone forever. Similarly, when some aspect of a culture or indigenous people is lost, some unique product of cultural evolution is gone too.

If that doesn't do it, there is a utilitarian motivation. “There could be a benefit to us from the thousands of different people around the world who have the most intimate knowledge of their natural environment," Loh said. "The ways in which it is possible to survive in that environment, the ways in which different plants and animals can be used, how they're caught or gathered or hunted, how they're prepared or cooked or stored, or what uses they can be put to, whether they have any medicinal value—all of that knowledge, and this is a vast knowledge bank, is being eroded.”

Researchers with the Hans Rausing Endangered Languages Project at the School of Oriental and African Studies in London once wrote that "every last word means another lost world." We could consider language just a proxy for culture, but that ignores the nuance that words bring to our lived experience. One language's very specific word for a particular feeling—say, the Portuguese word saudade, defined as a feeling of “longing” that’s “characteristic of the Brazilian temperament”—might in fact facilitate the experience of that feeling, or at least the recognition of it.

Words are more than just signifiers, they hold meaning on their own; according to legend Charles V, a Holy Roman Emperor, used Spanish when he spoke to God, French when he spoke to men, Italian when he spoke to women, and German to converse with his horse. In an essay on speaking multiple languages, novelist Ben Faccini recalled his French-speaking father's distaste of all the English translations for "tant pis." "'Too bad’, ‘never mind’ or ‘oh well’ didn’t quite do it justice, and the accompanying gestures certainly weren’t the same either," Faccini wrote.

Losing languages threatens to put us at risk of, as Australian linguist Peter Mühlhäusler called it, landing in “cultural blindspots,” or not recognizing other ways of being, thinking, and speaking. “That’s undoubtedly the most crucial global consequence of cultural and linguistic diversity loss, as we ignore the lessons of other ways of being human at our own peril,” Maffi said.

In 1981, the Stanford University biologist Paul Ehrlich came up with the "rivet-popper" hypothesis for biodiversity. Rivets hold the body of an airplane together, and he thought of them as a metaphor for our global ecosystem. There's likely a certain amount of redundancy, in species, in languages—just like there are planes that have more rivets than they need. If you remove one, or three, or five, the plane will probably stay in the air. But if you keep popping the rivets off, you risk a total collapse, and it's unclear which rivet will be the one to cause the whole plane to break into pieces.

“I increasingly believe that culture and nature are sort of interrelated,” Gorenflo said. “I don’t think that you can maintain high levels of biodiversity in a lot of these places without maintaining the cultural diversity that is associated with them all over the place, in all kinds of different ecosystems. I think there’s a need to maintain both, or lose both, but you can’t just keep one and not the other.”

Sign up for our newsletter to get the best of VICE delivered to your inbox daily.