While names like Patton, Hitler, and Churchill occur frequently in discussions of World War II, relatively few people mention names like John Brown, Chester Nez, Lloyd Oliver, or Allen Dale June. Yet all of these men, and hundreds more, were key figures in bringing the Allied forces to victory. As members of the Navajo Nation, they were recruited for an audacious project, forming a network of communications operators who transmitted information through their unique and unwritten language. These "Code Talkers," as they came to be known, occupied the front lines of major battles in the Pacific, allowing the U.S. military to send important messages in near-total secrecy.

The Navajo Code Talkers toiled in relative obscurity, silenced by classified mandates and a tendency to keep their heroic efforts to themselves. They often worked under extreme duress and spectacular violence, never once wavering from their mission: Using their complex language to outsmart and outmaneuver their foes.

An Un-Crackable Code

The project got its start in the early 1940s with Philip Johnston, an American World War I veteran who grew up on a Navajo reservation, where his father was a missionary. After spending his childhood on the reservation, Johnston was familiar with the Navajo language, a complicated spoken tongue understood by fewer than about 28 people—mostly anthropologists and missionaries—outside of the Navajo Nation. He even served as an interpreter, at age 9, for Navajos meeting with Theodore Roosevelt in 1901, in which the Navajos lobbied for better conditions for their people.

One day in 1942, Johnston was reading a newspaper article about an armored division in Louisiana looking to develop a code based on a Native American language. He thought that Navajo might be just the language they were looking for.

Johnston headed for a local naval office and got routed to the headquarters of the Eleventh Naval District in San Diego, California. There, he met Major James E. Jones, and explained his theory—that the Navajos communicated with incredible complexity, and it would be virtually impossible for messages in their language to be cracked.

Jones listened with a mixture of curiosity and skepticism. Language from another Native American tribe, the Choctaw, had been used during World War I under a similar belief it would be difficult for the enemy to understand. It had been employed with great success near the end of the war, but in the years that followed, the Germans had gone on to pose as students and anthropologists in the United States in an attempt to learn Choctaw, as well as Cherokee and Comanche. It was possible they were now capable of breaching another indigenous tongue.

Then Johnston began speaking Navajo—and Jones was impressed. The complex language intrigued him enough to agree to more complete demonstration in two weeks, in which messages would be encoded and then decoded by members of the Navajo Nation. In the interim, Johnston wrote an impassioned letter explaining the language and why he felt it would be impenetrable. He sent a copy to Jones and Major General Clayton B. Vogel, the commanding general of the Amphibious Corps, Pacific Fleet, who also agreed to show up for the exercise.

Faster Than a Machine

Johnston contacted four Navajo men and brought them to Camp Elliott, just outside San Diego, on February 27, 1942, for the demonstration. The next day, Vogel gave the team six messages and 45 minutes to figure out a method for encryption. When he returned, the men were able to create a code in Navajo, relay it, decode it, and recite it back in English, all in a matter of minutes. Military encryption machines could take hours.

Jones's skepticism vanished. So did Vogel's, who wrote a letter recommending the Marine Corps recruit 200 Navajos for the Amphibious Corps, Pacific Fleet. On May 5, 1942, 29 Navajos who had been gathered by Marine personnel at Fort Defiance, Shiprock, and Fort Wingate arrived in San Diego for basic training—and to begin arranging a code that would prove un-crackable for even the most determined Axis intelligence officers. Despite being in his forties, Johnston enlisted later that year to help train the recruits.

Some of the Navajo men who worked on the code volunteered for service, while others were drafted. Many in the tribe displayed a fierce patriotism and willingness to fight, even amid ongoing tensions with the U.S. government. According to The Code Book by Simon Singh, a number of Navajo even lied about their age (some were as young as 15) to join, or gorged on bananas and water to make minimum weight requirements. Most were enthusiastic about fighting the Axis powers, even though their mission took them by surprise. "All I thought when I went in [was that] the Marine Corps was going to give me a belt of ammunition, and a rifle, a steel helmet, and a uniform," Chester Nez, one of the Navajo recruited, said in 2004. "Go and shoot some of those Japanese. That's what I thought. But later on they told us differently … [a different] purpose of why they got us in."

Portions of the code were relatively straightforward. The Navajo used words for birds to describe specific aircraft: A fighter plane was da-he-tih-hi, the Navajo word for "hummingbird." A bomber plane was jay-sho, or "buzzard." A patrol plane was ga-gih, or "crow."

For military terms that had no obvious correlation, the team used a words-for-letters system, with one or more words assigned to each letter of the English alphabet. The letter A was represented by wol-la-chee ("ant"), be-la-sana ("apple"), or tse-nill ("axe"). The variety offered additional protection against a breach in security. Communicating the name of the island of Tarawa, for example, would be turkey-ant-rabbit-ant-weasel-ant, or than-zie, wol-la-chee, gah, wol-la-chee, gloe-ih, wol-la-chee.

The vocabulary began with 211 words, but eventually grew to 411. For security purposes, the code could not be written down and carried. The men would have to memorize the words that represented the English letters and military terms. They would need to know that the hard-shelled tortoise, or chay-da-gahi, meant another kind of hard shell: a tank. Because their culture was preserved via oral history, memorization came easily to most.

Perfection Under Pressure

In total, between 375 and 420 Navajos were recruited for secure transmission work. The Navajo radio operators—who later came to be known as Code Talkers—were dispatched to virtually every major Marine presence in the Pacific theater. They worked in pairs: One remained behind the lines and one transmitted via radio from the heat of battle, sometimes working while under enemy fire or during shocking displays of wartime violence. In author Doris Paul's book The Navajo Code Talkers, one Code Talker recalled: "If you so much as held up your head up six inches, you were gone, the fire was so intense." He also related an enemy attack that left a buddy in the trench dead, his blood covering the Navajo's hand as he radioed in for help.

Despite the extremely stressful conditions, the messages were delivered flawlessly. The Navajo Code Talkers participated in operations in Guam, Palau, and Okinawa; at Iwo Jima, six Code Talkers worked around the clock, delivering between 600 and 800 messages with no errors. The signal officer at Iwo Jima, Major Howard Connor, later remarked that the Marines would not have succeeded there if it weren't for the Navajo.

Despite its successes, the program was not without flaws. The Marine Corps likely could have used more Code Talkers, yet Navajos enlisting through the Selective Service rarely went to the Marines. Plus, not all stations using the code could communicate with one another: If one had a Navajo operator and one did not, there was no one to decipher messages. And on a few occasions, American soldiers captured Navajo, believing them to be Japanese. Many squads took to escorting Navajo Code Talkers with personal bodyguards to avoid such incidents.

After the war's end, it would be nearly 25 years before the Code Talkers' mission was declassified and the Navajos' efforts would become part of the historical record. In 1982, President Ronald Reagan awarded members of the group with a Certificate of Recognition, and acknowledged their contribution with a Navajo Code Talkers Day celebrated on August 14 every year. In 2000, Bill Clinton signed a law awarding the Code Talkers the Congressional Gold Medal. The following year, George Bush presented the medal to four of the surviving members: John Brown, Chester Nez, Lloyd Oliver, and Allen Dale June. Traditionally silent about their contributions, the Navajos were able to take their rightful place among the giants of the war, speaking the words that helped end one of the greatest conflicts in modern history. Their code was never breached.