Edwin Benson has died and with him a language may also pass on.

Benson, of Twin Buttes on the Fort Berthold Indian Reservation in west-central North Dakota, was the last living person who could fluently speak Mandan, Forum Communications reports.

“He said he’d done enough now and he was tired,” his daughter, Heidi Hernandez, said of her dad’s efforts to keep the language alive. “This language which made Dad so well-known across the world, I’m afraid it’s extinct.”

Benson’s mother died when he was young so he was raised mostly by his grandfather, who spoke only the Mandan language and did not allow English to be spoken in his home.

His name used to be Ma-doke-wa-des-she, he said.

“It’s sad that I can’t speak my language that I knew, the first language that I knew, and to grow old with, to no one today. To no one at all. And it’s a lonely life,” he told the Bismarck Tribune in a 2009 interview.

Benson was 85.

(h/t: Paul Tosto)