James Woodenlegs first learned to communicate using Plains Indians Sign Language from his family, when he was growing up on the Northern Cheyenne Reservation in Montana. Known as "hand talk" or "sign talk," the language has been used by both deaf and hearing Indians from Canada to the Gulf of Mexico for at least 200 years, possibly much longer.

"I went to the Montana School for the Deaf, and American Sign Language was used there," says Woodenlegs. "But, Indian Sign Language is such a part of who I am, my culture, and I really wanted to keep that going."

Woodenlegs is working with sign language scholars Jeffrey Davis and Melanie McKay-Cody to document and preserve hand talk, one of thousands of the world's endangered languages.

With help from the National Science Foundation (NSF), they are conducting field research to find current users of hand talk and compile a dictionary. The three are videotaping interviews with Northern Cheyenne, Assiniboine, Sioux, Crow, and several other tribes.

"I think linguistics can tell us not only about cognition and culture but also our history," explains Davis, an associate professor of sign language linguistics at the University of Tennessee in Knoxville. "We’re identifying the nouns and the verbs and other linguistic features and discovering how these form grammar."

McKay-Cody, an assistant professor of sign language at William Woods University in Fulton, Mo., is a Chickamauga Cherokee/Choctaw. She is the first deaf researcher to specialize in North American Indian Sign Language, and has worked closely with American Indian/Alaska Native/First Nation deaf and hard of hearing people to promote Deaf Native Studies.

"We are collecting these videos and not just leaving them on a shelf to collect dust. We are annotating, captioning and sharing them," explains McKay-Cody. "Our goal is to use these for education and to raise awareness about this language, to use it in teaching — that's my goal, to educate others."

A chance discovery at the National Archives and Records Administration led Davis to a treasure trove of historical films documenting the early uses of hand talk by dozens of tribes spread across North America.

In the early 1990s, Davis struck up a conversation with some folks looking at old films and photos for a Ken Burns documentary on baseball.

"We got stranded at the National Archives during a blizzard," recalls Davis. "And the people working on that project said, 'Well, you know, there is a collection of old films with Indians signing back there, have you seen those?' I couldn't believe that these films existed!"

The old films were created as a labor of love by retired Army General Hugh Scott, who not only studied the language, but learned it. He also arranged for chiefs and tribal elders to gather in Montana in 1930 to share their stories and histories.

While some of the films were funded by the Department of the Interior during the Great Depression, Scott used his own money to continue chronicling this signed lingua franca.

The University of Tennessee funded the digitization of the old films, and these long-forgotten images are now on a website supported by the Smithsonian Institution, the National Endowment for the Humanities, and NSF.

McKay-Cody and Woodenlegs recently visited the Tennessee School for the Deaf in Knoxville to introduce students to this expressive and elegant sign language.

It was traditionally used for storytelling, rituals and in stealthy situations, such as battle and hunting.

"I like to hunt with my people," says Woodenlegs. "I would sign to somebody else behind another tree and we would sign to each other, 'Go to this tree.' If we were to yell to each other, or call out to each other, the animals would run, so sign language is great for hunting."

Davis says there is an extreme urgency in studying the world's 6,000 distinct human languages, among them at least a few hundred sign languages.

"It's estimated that at least half of these languages are in danger. Languages die every year for different reasons," explains Davis. "A tsunami can destroy an entire village, and a language can be lost. In Africa, there is an adage, 'When an elder dies, it's like losing a library.'"

James Woodenlegs stressed the need for keeping history alive as he bid farewell to the students at the School for the Deaf. "All of these good stories have been passed down. Remember them, and use them, don't just ignore them. Remember and use the stories, the things that your teachers tell you. Be grateful all of the time, to your teachers, to other children, to your parents. Gratitude is so important."

With those words of wisdom, he taught the students the hand talk sign for "See you later!"

Davis is optimistic about preserving hand talk on video, but more importantly in Indian communities where sign language once thrived. "You see the elders still teaching it to their grandchildren. Native community members still know the language, and that's what makes it so exciting. People are still motivated to learn and use it," says Davis.

This story was originally written for Science Nation and was republished with permission here. Video: Science NationMiles O'Brien/Science Nation Correspondent, Marsha Walton/Science Nation Producer.