KE'EAU, Hawai'i — Portraits in the school's library are not of U.S. presidents but Hawaiian royalty, from King Kamehameha to Princess Ka'iulani. Near the classroom door, rubber slippers are tidily lined up by the students, who go barefoot. The calendar shows it's the month of "Malaki."

Hawaiian language and culture fill the hallways and playgrounds of Ke Kula 'O Nawahiokalani-'opu'u Iki and define the mission of the school with the sizable name — Nawahi for short. English is allowed only during the one-hour English class.

A major effort is under way to revive and preserve Hawai'i's native tongue, including so-called immersion schools, marking their 20th anniversary. Courses from math to science are taught entirely in Hawaiian.

The language was nearly wiped out after being banned from schools across the islands for nearly a century. In 1983, when a small group of educators founded a key Hawaiian language revival program, fewer than 50 children spoke the language. Today, the rhythmic, fluid sounds of Hawaiian are used proficiently by more than 2,000 children.

"It's important because I'm the only one in my family who speaks Hawaiian," said Leiali'i Lee, a 10th-grader at Nawahi, one of 23 immersion programs in the state. "I can make a difference and I can revive my language."

Nawahi, which has nearly 200 students from preschool through 12th grade, was founded in 1994 as a laboratory school affiliated with the University of Hawai'i-Hilo. Students are taught Hawaiian traditions and culture, such as growing sweet potatoes, building canoes and understanding the land.

The school has succeeded despite financial and political challenges, and skepticism about educating in Hawaiian, the only indigenous language in the United States that is an official state language.

Although about half the students are from low-income families, the school boasts a perfect graduation rate, with 80 percent moving on to college, well above the statewide average for public schools.

A visit to Nawahi reveals its formula for success: small classes, a family-oriented environment and teachers dedicated to rescuing the Hawaiian language.

"If you're not successful, I'm going to make you successful. That is my responsibility," said teacher Hiapo Perreira, who in 2002 became the first person in the country to receive a master's degree in Hawaiian and who is now in UH-Hilo's new doctoral program.

"If my dream were to come true tomorrow ..., every Hawaiian would know Hawaiian," Perreira said.

Student Akala Neves, a junior who hopes to attend Harvard or Stanford, explained why that's important: "If you know who you are, you're confident and you don't have to be afraid. ... This school teaches us we can compete with everybody."

In the tiny school library, besides the portraits of royalty, there are dozens of framed pictures of the students' families. "We don't want to do bad because our grandparents are watching," said Lee, the 10th grader.

Books are in Hawaiian, including many originally in English. With very few children's books available in Hawaiian, parents paste translations on top of the English text. So, for example, Shel Silverstein's popular book, "The Giving Tree," becomes "O Kumula'au Aloha."

Critics say students could be held back by learning a language that's not "viable" in today's world. But school officials say Nawahi students have exceeded peers in standardized English tests.

Studies also have suggested that highly bilingual students tend to have higher cognitive abilities.

"What people don't realize is that we speak English. Right after we leave this campus, it's English," Akala said. "When we go home, we speak English. So we have so much English."

Kapa'anaokalaokeola Oliveira, an assistant professor of Hawaiian at UH, also expressed encouragement about the once-forbidden language. "Today, I think there's a revitalization. People are encouraging their children to speak Hawaiian," she said.

Still, Hawaiian is far from being saved.

"It's still very close to being dead," said William "Pila" Wilson, one of the founders of 'Aha Punana Leo language program and chairman of the Hawaiian program at UH-Hilo. "A language is dead when children are no longer speaking it. Once children stopped speaking Hawaiian, especially to each other, we knew it was going to end."

Almost all the students at Nawahi started out speaking English, but Kalehua Ontai, a bashful 11-year-old girl whose personality comes to life when she plays the 'ukulele, only started learning English last year.

"The Hawaiian language is my first language. The Hawaiian language is the language of my ancestors and it's the language of my land," she said.

One of the few students outside Ni'ihau who learned Hawaiian at home, she is an example of the progress made in the revival of the language.

At Nawahi, the school day begins at 7:45 a.m. with the haunting moan of the conch shell, which serves as a school bell and calls everyone to gather in the open-air courtyard.

Through chant, the students ask the teachers for permission to enter.

Throughout the day, students use chants, some resounding and forceful, others playful and light.

They end the day with song or prayer — echoing the cadences of their ancestors, which nearly went silent.