COARSEGOLD, Calif. — Inside a classroom of some 20 adults and children studying the language of their tribe, a university linguist pointed out that Chukchansi has no “r” sound and that two consonants never follow each other. The comments seemed to stir forgotten childhood memories in Holly Wyatt, 69, the only fluent speaker present, who was serving as a living reference book.

“My mother used to call Richard ‘Lichad,’ ” Ms. Wyatt blurted out, referring to a relative. “It just popped into my head.”

Using revenues from their casino here in the Sierra Nevada foothills, the Chukchansi Indians recently pledged $1 million over five years to California State University, Fresno, to help preserve their unwritten language. Linguists from the university will create a dictionary, assemble texts and help teach the language at weekly courses like the one on a recent evening.

The donation caps efforts in recent years by American Indian tribes across the nation to bring back their tongues before the death of their sole surviving speakers. With coffers flush from casino gambling, dozens of tribes have donated to universities or have directly hired linguists, buttressing the work of researchers dependent on government grants, experts say.