At approximately 100 feet, the Q’eswachaka stretches across the edges of two cliffs overlooking the Apurímac River. It is rebuilt yearly by four Quechua communities—the Choccayhua, Chaupibanda, Ccollana Quehue, and Huinchiri—who come together every second week of June to spend three days building the bridge and a fourth celebrating its completion. Before the work can begin, the paqo, or “Andean priest,” asks for protection and permission. Throughout the days following, he keeps a fire burning at one of the bridge’s extremes, the smoke of which, it is believed, carries offerings to the mountains.

To the people who have been gathering to take down, rebuild, and honor this structure for the past 600 years, the bridge is an apu, a god, and the Apurímac River flowing beneath it houses a siren, who controls the fates of those who cross it. To erect the new Q’eswachaka, one of the builders ties a cable around his waist and edges his way across last year’s structure. Once this connection is secure and ready to transport supplies and other cables, the old bridge is cut loose and released as an offering to the siren.

This rope bridge is the last vestige of many such links in the 20,000-mile network of pathways that connected the Inca across Colombia, Ecuador, Peru, Bolivia, Argentina, and Chile. In the words of MIT professor John Ochsendorf, a structural engineer and historian of construction, who coordinated the building of a Q’eswachaka across the National Mall for the 2015 Smithsonian Folklife Festival, “you have native hands, speaking native voices, using native materials on the site, and native techniques, and so this is, I believe, unique in the Americas in terms of cultural continuity.”

Despite its recent acclaim, the bridge may not survive the next generation. In large part, that’s because the language in which it is constructed and venerated is quickly disappearing.

“There used to be coins of silver and gold,” says Mario Marquere Alata, a conservator with Peru's Ministry of Culture, speaking of the costly gifts that the community used to pay in tribute to the Q’eswachaka. “But now there’s nothing like that.” Now that the new generation is losing touch with older traditions, he says, they give little chocolates or trinkets instead of coins. This devaluing of the tradition, as he calls it, goes hand in hand with the loss of the language in which the bridge’s construction and rites are conducted. Only 40 percent of the younger generation speak the language of their Inca ancestors. Since the ancestral language is integral to the rites associated with the Q’eswachaka, the decline of speakers will make it difficult for the tradition to continue. This loss poses a serious threat to a culture where spirituality is so intrinsic that there is no language to describe it.

"Quechuas don’t have a concept of ‘sacred’ and don’t have a concept of ‘spirituality,’” says Bruce Mannheim, a professor of anthropology at the University of Michigan and author of The Language of the Inka since the European Invasion. “It’s a different way of thinking about the world. There is no division between the sacred and the profane, so you could say they’re always living in a sacred world or you can say they’re always living in a profane world. Neither statement makes sense in Quechua. Neither statement really does justice to what they are doing.”

Mannheim focuses specifically on Southern Peruvian Quechua, the lingua franca of Inca administrators that is still spoken by the communities that celebrate the Q’eswachaka. According to him, external pressures and changes in the educational system have caused the sharp decline in Quechua speakers over a half century. “People recognize that, for economic reasons, they want to learn Spanish and they want their children to learn Spanish, and they don’t have a great deal of choice in the matter.” Southern Peruvian Quechua has had to adapt to a changing world, adding not only terms for new technological inventions like computers, but also borrowing words like “government,” “military,” and “taxes” from Spanish.

Like the language of those who build it, the Q’eswachaka links traces the past and present together. “It is forbidden to fly over the bridge with drones,” reads the brochure distributed by the Peruvian Ministry of Culture, during the three days of building. That’s because these buzzing intruders threaten to distract and endanger bridge master Victoriano Arizapana and his teammate as they straddle the bridge’s cables and weave its floor by hand, working from opposite ends toward the center. In this culture, the right to build the bridge is passed down through bloodlines—Arizapana’s male ancestors had directed operations for generations before him. The plans for the bridge are communicated not through written instructions or diagrams, but through apprenticeship—though it is said that there are designs from the Inca hidden in the nearby rocks.

Now the Q’eswachaka is made exclusively of a grass known as q’oya, but it used to incorporate plant materials that have since disappeared and even llama leather, both of which made it strong enough to serve the needs of the communities that it tied together. These days, a nearby steel truss bridge enables the transport of cars and supplies, and the Q’eswachaka’s construction and rituals are kept alive by tourism rather than functionality.

Southern Peruvian is not the only Quechua language at risk of being erased. “Quechua,” a label imposed by Spanish colonists, is not a uniform system, but rather a patchwork of languages and dialects that span across the original domain of the Inca. Thanks in large part to the Documenting Endangered Languages program cofunded by NEH and the National Science Foundation, there have been major recent efforts to document these diverse strains and make them accessible to an international audience. The University of Texas at Austin’s Archive of the Indigenous Languages of Latin America, for example, divides Quechua into four branches, with a total of 46 languages or dialects. The database provides recordings of many of these varieties as well as segments of related courses and information about the methods used by the scholars who collect and transcribe the content.

Three dialects of the branch of Quechua known as Yauyos were extinct by the time that Aviva Shimelman, also supported by the Documenting Endangered Languages program, began her fieldwork to record the remaining five. Shimelman, who was until recently based at the Max Planck Institute for the Science of Human History, spent three years in the mountains of the Yauyos province of southern Peru collecting and studying these dialects, and she came up with her own system for collecting the widest range of expression possible.

“It was like pulling teeth to get anything,” says Shimelman, describing her struggle to collect a wide range of words through direct interviews. “I would get: ‘I was born, I was married, I herded my animals, my husband died.’” The repetition in these conversations wasn’t giving her the range of data she needed. “And then, I kind of stumbled across this thing,” she says. A man fell into a ravine and died, and “there was no way they were going to get a coroner to come.” The 30 people who went down to recover his body invited her to film them. As she recorded their conversations, she came upon a new methodology. Suddenly, “I had the diversity of expression, the diversity of vocabulary, that I wasn’t getting.”

From then on, Shimelman began filming everything from yarn-spinning to protests and then recording community members as they commented on the clips. Using this method, she collected words like “coagulate” that aren’t on the standard list of terms used by linguists. “What’s happening in their lives?” she asks. “Where’s that food coming from? It’s from the sheep. What’s going to happen when you kill an animal? It bleeds. What’s going to happen when it bleeds? That blood is going to coagulate.” By recording commentaries on footage of activities like food production, Shimelman documented a lexicon that would not have been available otherwise. “Certainly, video recordings are important as a standard part of the process of language documentation, but using them the way I did? It was just one of the nice, on-the-way discoveries.”

Shimelman estimates that there are fewer than 450 speakers of Yauyos Quechua remaining, most of whom are fully bilingual in Spanish. The plight of the Yauyos dialects is one that is reflected in languages around the globe. “I don’t think that the situation in Yauyos is unique at all,” she says. “I think you have a standard situation where the region that had formerly been isolated which protected the language is increasingly brought into a national system.”

“Isolation had preserved the language,” says Shimelman. “But what’s going to happen when you don’t have that critical mass? And as soon as that road comes in, and people are a lot more mobile, and people are going to cities to work, staying in cities, the populations will dissipate.”

Through her research, Shimelman found about 2,000 words and then created a detailed Grammar of Yauyos Quechua that will serve students and scholars well into the future. She identifies both scientific and humanitarian reasons for preserving these dialects before they disappear. “We’re losing more than half of our data,” says Shimelman, “And it’s not just half. It’s the half that’s going to challenge our current theories.” The disappearance of dialects like the ones she studies will mean more than the loss of crucial information. “There is the part about every language having a unique view on the world, and we are losing our perspective. We are losing our ability to think in our world. And that’s worth gold.”