On a February school day, squealing, shouting preschoolers riding red and yellow bouncy balls stampede across the Hinono'eitiino'oowu'  (Arapaho Language Lodge) language immersion classroom in Ethete. They swarm strangers, grinning gap-toothed grins, and show off what they know in Arapaho, pointing to the images that cover the walls from floor to ceiling -- raindrops, stars, turtles, a rabbit jumping over a fence, a couple dancing.

"Come to my workshop, and I'll teach you 16 phrases in Arapaho in 10 minutes," Greymorning had told me over the phone as I began to research language revitalization efforts on the Wind River Reservation. Greymorning left the reservation in 1994 for the University of Montana in Missoula. He still advises the immersion programs from afar. Over the years, however, he has been consistently frustrated by what he considers teachers' and administrators' failure to implement his methods for teaching Arapaho. So in 2009, Greymorning decided to make what he described as a "final" trip from Montana to conduct yet another teach-in on the Wind River Reservation.

Hands on hips, he stares down the small group assembled before him, talking about his immersion program at the University of Montana. "In my (college) classroom, after nine hours, students have learned 200 phrases they can manipulate in three different ways. Can any of the kids who graduate from schools here do that?" The teachers murmur and shake their heads. No. This is unheard of in the immersion or public school programs -- even for students who've taken Arapaho from kindergarten through high school.

Greymorning is convinced that the problem lies in teachers' failure to implement his curriculum. His system doesn't introduce writing and reading until students have mastered speaking. This grates against standard methods of teaching a second language, especially in the public school system, which relies heavily on written assessment. Greymorning also forbids the use of English as a crutch -- perhaps the hardest rule for teachers to adhere to, particularly if their own knowledge of Arapaho is not solid.

"It's like you're swimming around in circles," says Greymorning, referring to teachers' tendency to lapse into English. "I'm here trying to throw you a rope, but you keep trying to do the same thing that isn't working."

The teachers stare back at Greymorning, some of them balefully. One commanding middle-aged woman makes a point of talking to her neighbor as he speaks. Easy for you to say, her attitude suggests. You try controlling a classroom full of rowdy preschoolers without ever using English. (Greymorning gets a frosty reception from some people on the reservation. "Greymorning left," they say, suggesting that if he'd really wanted to help, he would have stayed.)

Unfazed, Greymorning suddenly tells me to stand up. He takes me over to a wall of pictures that are grouped according to his system, which is tailored to Arapaho grammar. A few of the older ladies smile encouragement.

Greymorning points at the first image -- a little girl -- and says, distinctly: hiseihihi'. Hiseihihi,' I repeat, palms sweating. Ci' nihii beeseitii says Greymorning. Try again, his expression says, but louder, more confidently. After we go through the first set of words, Greymorning quizzes me. I slap my hand down on the images as he names them, repeating the words again. It feels like a game -- a far cry from filling in bubbles on multiple-choice tests.

As we build quickly from four to 16 words, however, I start to make mistakes. Wo'ooo, the word for "cat," is harder to pronounce -- the vowels trip over themselves, surging forward. When I can't figure out what Greymorning means by 3i'okuuto'oo, the Arapaho word for chair, he tells me in Arapaho to sit down in a chair, and then to stand up. At first, I can't figure out what he's referring to. Then it clicks: In Arapaho, the word "sit" -- ceenoku is related to the word "chair:" 3i'okuuto'oo. I point to the image of the chair and bask in applause, feeling like a precocious 5-year-old.

Next, Greymorning quizzes Robert Hall, a 20-year-old Blackfoot man who has studied Arapaho with him at the University of Montana. As the older people listen to Hall -- who isn't even Arapaho -- give life and breath to their language, the atmosphere in the room thaws further. "I used to think (my native language) was an old person's language," says Hall. But after he left for college, he realized that "the privilege of being from the rez is understanding that language is a spiritual thing. I want to pray to my ancestors through my own language. It has to come from the heart. The English version is not from the heart."

Nowadays, young people are more likely to say "S'up" than "Tous" in greeting, laments Arapaho teacher Liz Lone Bear -- more likely to learn Spanish and dress like L.A. gangsters than to speak Arapaho. But sometimes, she admits, the elders make it worse by making fun of young people who are trying to learn. "That's real ignorant. Instead of laughing, we need encouragement," notes an older man. The group nods agreement. Hall looks around, a little sadly, and says, "We all need help. Our elders need help. I need help."