FARGO - Edwin Benson stumbles through a few false starts before he catches his rhythm telling an old story about how a coyote turned into a buffalo.

He sits on a stool draped with a woolly buffalo hide across from a man recording him with a digital video camera mounted on a tripod.

After only a few minutes, Benson holds up his hand to stop the camera.

"My throat got a tickle," he explains. "I didn't want to cough."

Then, once Benson catches his stride, his tale of a conniving, hungry coyote tempted by a lame buffalo calf begins to unfold.

Benson's occasional apology in English interrupts his low rumble of guttural sounds, with inflections that rise and fall like rolling hills. He's speaking Mandan, the first language he spoke growing up in his grandfather's house along the Little Missouri River.

Now, with more than seven decades behind him, Benson's command of his native tongue is rusty from disuse.

He speaks Mandan mostly on ceremonial occasions and in the classroom, where he teaches fundamentals of the language to children in a school three miles from his rural home on the Fort Berthold Reservation, which straddles Lake Sakakawea in west-central North Dakota.

Benson has watched as the language of his childhood has disappeared around him, dying a little more with the passing of each elder in a dwindling pool of fluent native speakers. Now only a handful remain.

Linguists consider Benson the last truly fluent speaker of Mandan. Even his wife, Annette, who watches quietly from the corner as Benson tells his story, can't speak the language.

"It's a lonely life, it's a lonely life," he said. "If I want to say any Mandan words, I've got to say it to myself and I don't want to say it too loud, otherwise people might think I'm going wacky."

When Edwin Benson dies, the main living library of the Mandan language, a language spoken for thousands of years along the valley of the Upper Missouri River and its tributaries, will die along with him.

The Mandan Edwin Benson learned while growing up often came to him as a stream of stern paternalistic commands and lessons.

His teacher was his grandfather, who raised him and taught him some of the old ways the Mandan had followed for centuries.

Ben Benson was a living link to the ancient practices of the Mandan. He was born in the latter part of the 1800s in Like-a-Fishhook Village, the last traditional earth-lodge village of the Mandan, Hidatsa and Arikara, three neighboring tribes that came together as their numbers dwindled from disease.

Traditional ways were in long decline when Edwin Benson was born in 1932. Like-a-Fishhook Village was abandoned in 1882 when its residents were moved to the reservation's agency village, Elbowoods. Cabins made from split logs replaced the domed earthen lodges.

After his mother died, his grandfather kept Edwin, the youngest of five children, at home with him. Several sisters were sent to a boarding school in Billings, Mont., where speaking native languages was forbidden.

Growing up in his grandfather's household, Benson heard and spoke only Mandan. He encountered English when he first attended school, at age 7.

"English language didn't make no sense at all when I attended classes," he said. "But I picked up the language watching what others did."

He served a tour in the Army, then spent a couple of years as an itinerant laborer in the Pacific Northwest, a time when he drank heavily.

After he returned to Fort Berthold, he married in 1955 and eventually settled on high land that had been in his mother's family, three miles from the Mandan community of Twin Buttes.

Occasionally, Benson drives down as close as the waters of Lake Sakakawea will allow, to the place where the Little Missouri joins the Missouri River, where his grandfather's house and father's cabin once stood beneath the cottonwoods.

"I still feel bad when I go back down there to look," he said. "A lot of our ways, how we did things, is all kind of buried there under water, under the big body of water.

"My language is down there, my culture is down there," he said. "It's not really with me."