WINDOW ROCK, Ariz. — Allen Dale June, one of the 29 original Navajo Code Talkers who confounded the Japanese during World War II by transmitting messages in their native language, has died. He was 91.

June died of natural causes Wednesday night at a veterans hospital in Prescott, his wife, Virginia, told The Associated Press on Thursday.

His health had been failing since earlier this year when he was hospitalized for a urinary tract infection and kidney failure because he wasn’t drinking enough water, his wife said. He was hospitalized again two months ago after visiting family on the Navajo Nation and was transferred from a Flagstaff hospital to Prescott, where he was under round-the-clock care.

The Code Talkers took part in every assault the Marines conducted in the Pacific from 1942 to 1945. They sent thousands of messages without error on Japanese troop movements, battlefield tactics and other communications critical to the war’s ultimate outcome.

Several hundred Navajos served as Code Talkers during the war, but a group of 29 that included June developed the code based on their native language. Their role in the war wasn’t declassified until 1968.

June, who attained the rank of sergeant, received the Congressional Gold Medal in 2001 along with other members of the original Code Talkers.

With his death, only two of the 29 are still living.

“The Navajo Nation lost a great warrior,” Tribal Council Speaker Lawrence T. Morgan said in a statement. “His unique service to his country brought positive attention to the Navajo Nation. He will be missed.”

June first tried to sign up for the Marines in his hometown of Kaibeto on the Navajo Nation, but a recruiter told him he was too young. He then traveled to the reservation town of Chinle to enlist — because he figured people there wouldn’t recognize him — and he could lie about his age and forge his father’s signature, Virginia June said.

Even after the code was declassified in 1968, June said little about his role as a Code Talker because he viewed it as bragging, his wife said. Anyone who saw him in the past several years might have been able to guess he was a Code Talker, as he wore a red Navajo Code Talker cap with his name on it wherever he went and a black leather jacket with “Marines” written across the back. He completed his look with a bolo tie that had a large turquoise stone.

Virginia June routinely handed out cards bearing Allen June’s picture and rank in the Marines that he had autographed.

Besides his wife, Allen June is survived by 10 children. Funeral services are scheduled for Monday in Page, with burial in Kaibeto.