The task

When Platoon 382 finished boot camp, the twenty-nine men went to Camp Elliott for radio training and were given an assignment no Marine had been given before. They were to make a code out of their own language. The officers who supervised them could tell them what military terms a code needed and how radio procedure worked, but none of them spoke Navajo. The choice of every word was left to the Navajo Marines (Prologue).

Chester Nez later remembered the work as a group effort, men debating which Navajo word best fit a military idea and testing whether everyone would hear it the same way. In his account, three more Navajo Marines who were already in the Corps, Felix Yazzie, Ross Haskie and Wilson Price, joined to help with military terms; for him, he said, it was “the original 32” (HistoryNet). The rules they settled on were simple enough to remember under fire and strange enough to baffle a listener.

Birds, fish and clans

The first rule was substitution. Navajo had no words for a dive bomber or a destroyer, so the men chose ordinary Navajo words for things in their own world and gave them military meanings. Aircraft became birds. A fighter plane, fast and darting, was da-he-tih-hi, the hummingbird; a dive bomber was gini, the chicken hawk; a bomber was jay-sho, the buzzard; a patrol plane ga-gih, the crow; a transport plane atsah, the eagle. Bombs dropped from them were a-ye-shi, eggs.

Ships became creatures of the sea. A battleship was lo-tso, whale; a cruiser lo-tso-yazzie, small whale; a destroyer ca-lo, shark; a submarine besh-lo, iron fish. An aircraft carrier was tsidi-moffa-ye-hi, bird carrier. On land a tank was chay-da-gahi, tortoise, and a hand grenade ni-ma-si, potatoes. A mortar was “sitting gun,” artillery “many big guns,” a sniper “pick ’em off.”

Military organization borrowed from Navajo social life. A corps was din-neh-ih, clan. A division was ashih-hi, salt, a regiment “edge water,” a battalion “red soil,” a platoon “mud,” a squad “black sheep.” Ranks were described by their insignia: a colonel was “silver eagle,” a major “gold oak leaf,” a captain “two silver bars.” Countries got descriptive names. America was ne-he-mah, “our mother”; Britain was “between waters”; China “braided hair”; Alaska “with winter.” Every term here is taken from the declassified dictionary (Naval History and Heritage Command).

An alphabet of animals

The second rule covered everything else. Names of islands, ships, officers and places, and any word without a code term, were spelled out letter by letter. For each English letter the men chose a Navajo word whose English translation began with that letter: wol-la-chee, ant, for A; shush, bear, for B; moasi, cat, for C; be, deer, for D; dzeh, elk, for E. The alphabet ended with besh-do-tliz, zinc, for Z.

The listener needed three steps to read a letter: hear the Navajo word, translate it into English and take the English word’s first letter. Anyone who did not speak Navajo was stopped at the first step. But a cryptographer who reviewed the system saw a weakness. In English some letters, E, T and A above all, appear far more often than others. In a long spelled-out message, a listener who could not understand a word could still count which sounds recurred most, and frequency counting is the oldest way to attack a substitution code. The answer was to give the commonest letters more than one word. The alphabet grew from 26 words to 44, with alternates for E, T, A, O, I, N, S, H, R, D, L and U. A, for instance, could be wol-la-chee (ant), be-la-sana (apple) or tse-nill (axe) (Prologue).

Try it

The vocabulary

The cards below come straight from the 1945 dictionary. Tap a card to turn it over and see the Navajo code word and its literal meaning, or filter by category.

The vocabulary grew as the war did. New weapons, new kinds of landing craft and new operations needed names, and the Marine Corps periodically revised the list. By most accounts it expanded from 211 terms to 411; a later Marine Corps article put the count of frequently used military terms at about 450, which may include later additions (CIA; Camp Lejeune). The dictionary that survives in the National Archives is the revision of 15 June 1945.

How a message moved

Speed came from what the method left out. A message enciphered on a machine had to be typed in, enciphered, transmitted as groups of letters, received, typed into a matching machine and deciphered, with a trained operator at each end. A message in the Navajo code went from voice to voice. The two code talkers had to be good, and they had to agree on every word, but they were doing in their heads what other systems did with paper and equipment.

How fast?

Claims about the code’s speed are often repeated and rarely sourced. The three that appear in official accounts are set side by side here. They measure different things, and none of them is a controlled experiment, but they all point the same way.

The best evidence for speed is not a stopwatch figure but the judgment of the officers who used it. In May 1943 division commanders reported that “excellent results had been achieved to date in the employment of Navajo code talkers,” and after Iwo Jima a signal officer’s report called the code “the simplest, fastest, and most reliable means” of sending secret orders over circuits exposed to interception (Marine Corps History Division; Prologue).

The code talker school

Once the first platoon had built the code, the Marine Corps needed more men who knew it. Philip Johnston, who had argued for the program, enlisted on 2 October 1942 at the rank of staff sergeant and spent the rest of the war training code talkers. Classes began that November; Johnston called the eight-week messenger course that followed boot camp “extremely intensive.” A second group of two hundred had been recommended in July 1942, and later plans called for fifty more recruits a month (Prologue).

Recruiting never caught up. By August 1943, the Marine Corps History Division records, 191 Navajo men had enrolled. Quotas were cut to twenty-five a month, the Corps arranged for volunteers to come through Selective Service, and it tried to transfer Navajo soldiers from the Army. By the end of the war somewhere between about 375 and 420 Navajo Marines had served as code talkers, and some Navajo Marines served without ever joining the program. Every code talker also had to be a Marine first: they carried rifles, dug foxholes and fought as infantry when they had to (Marine Corps History Division).

Because no copy of the code could be carried into combat, every man had to learn every word and use it the same way. That turned out to be the program’s hardest problem. Groups trained at different times and places developed slightly different habits, and officers in the field reported misunderstandings between code talkers from different classes. The Marine Corps responded by rotating men between divisions, revising the dictionary and, after Iwo Jima, recommending a single standard dictionary with refresher training every three months. Chapter 3 follows those problems into the field.

Could it be broken?

The Japanese heard the code; they never understood it. It had built-in protection against the most obvious danger, a code talker captured and forced to transmit. According to Chester Nez, a code talker made to send a message under duress would work in the Navajo words for “do or die,” warning the man at the other end (HistoryNet).

The strongest evidence that the code held comes from the story of a Navajo soldier who never learned it. Sgt. Joe Kieyoomia of New Mexico’s 200th Coast Artillery was captured when the Philippines fell in 1942 and survived the Bataan Death March. His captors at first took him for a Japanese American because of his name; when they accepted that he was Navajo, they ordered him to explain the Navajo messages their radio operators were intercepting. Kieyoomia could not. He recognized the words, but not what they meant in the code: the talk of birds, fish and potatoes made no sense to him. He was beaten and forced to stand naked in the snow until his feet froze. Asked decades later, he said he would not have told them even if he had known. “I salute the Code Talkers,” he said (Deseret News, 1995). Kieyoomia survived forty-three months as a prisoner, including the atomic bombing of Nagasaki.

The code’s security had a price that only the code talkers paid. Because the program stayed classified after the war in case it was needed again, the men who built and used it could not talk about what they had done for twenty-three years. That story is told in Chapter 5.

The Navajo Code Talkers chapters

Sources