They did try. And they did capture Navajo men. However, they were unsuccessful in using them to decipher the code. The reason was simple. The Navajo Code was a code that used Navajo. It was not spoken Navajo. To a Navajo speaker, who had not learned the code, a Navajo Code talker sending a message sounds like a string of unconnected Navajo words with no grammar. It was incomprehensible. So, when the Japanese captured a Navajo man named Joe Kieyoomia in the Philippines, he could not really help them even though they tortured him. It was nonsense to him.
The Navajo Code had to be learned and memorized. It was designed to transmit a word by word or letter by letter exact English message. They did not just chat in Navajo. That could have been understood by a Navajo speaker, but more importantly translation is never, ever exact. It would not transmit precise messages. There were about 400 words in the Code.
The first 31 Navajo Marines created the Code with the help of one non-Navajo speaker officer who knew cryptography. The first part of the Code was made to transmit English letters. For each English letter there were three (or sometimes just two) English words that started with that letter and then they were translated into Navajo words. In this way English words could be spelled out with a substitution code. The alternate words were randomly switched around. So, for English B there were the Navajo words for Badger, Bear and Barrel. In Navajo that is: nahashchʼidí, shash, and tóshjeeh. Or the letter A was Red Ant, Axe, or Apple. In Navajo that is: wóláchííʼ, tsénił , or bilasáana. The English letter D was: bįįh=deer, and łééchąąʼí =dog, and chʼįįdii= bad spiritual substance (devil).
For the letter substitution part of the Code the word “bad” could be spelled out a number of ways. To a regular Navajo speaker it would sound like: “Bear, Apple, Dog”. Or other times it could be “ Barrel, Red Ant, Bad Spirit (devil)”. Other times it could be “Badger, Axe, Deer”. As you can see, for just this short English word, “bad” there are many possibilities and to the combination of words used. To a Navajo speaker, all versions are nonsense. It gets worse for a Navajo speaker because normal Navajo conjugates in complex ways (ways an English or Japanese speaker would never dream of). These lists of words have no indicators of how they are connected. It is utterly non-grammatical.
Then to speed it up, and make it even harder to break, they substituted Navajo words for common military words that were often used in short military messages. None were just translations. A few you could figure out. For example, a Lieutenant was “one silver bar” in Navajo. A Major was “Gold Oak Leaf” n Navajo. Other things were less obvious like a Battleship was the word for Whale in Navajo. A Mine Sweeper was the Navajo word for Beaver.
A note here as it seems hard for some people to get this. Navajo is a modern and living language. There are, and were, perfectly useful Navajo words for submarines and battleships and tanks. They did not “make up words because they had no words for modern things”. This is an incorrect story that gets around in the media. There had been Navajo in the military before WWII. The Navajo language is different and perhaps more flexible than English. It is easy to generate new words. They borrow very few words and have words for any modern thing you can imagine. The words for telephone, or train, or nuclear power are all made from Navajo stem roots.
Because the Navajo Marines had memorized the Code there was no code book to capture. There was no machine to capture either. They could transmit it over open radio waves. They could decode it in a few minutes as opposed to the 30 minutes to two hours that other code systems at the time took. And, no Navajo speaker who had not learned the Code could make any sense out of it.
The Japanese had no published texts on Navajo. There was no internationally available description of the language. The Germans had not studied it at the time. The Japanese did suspect it was Navajo. Linguists thought it was in the Athabaskan language family. That would be pretty clear to a linguist. And Navajo had the biggest group of speakers of any Athabaskan language. That is why they tortured Joe Kieyoomia. But, he could not make sense of it. It was just a list of words with no grammar and no meaning.
For Japanese, even writing the language down from the radio broadcasts would be very hard. It has lots of sounds that are not in Japanese or in English. It is hard to tell where some words end or start because the glottal stop is a common consonant. Frequency analysis would have been hard because they did not use a single word for each letter. And some words stood for words instead of for a letter. The task of breaking it was very hard.
Here is an example of a coded message:
béésh łigai naaki joogii gini dibé tsénił áchį́į́h bee ąą ńdítį́hí joogi béésh łóó’ dóó łóóʼtsoh
When translated directly from Navajo into English it is:
“SILVER TWO BLUE JAY CHICKEN HAWK SHEEP AXE NOSE KEY BLUE JAY IRON FISH AND WHALE. “
You can see why a Navajo who did not know the Code would not be able to do much with that. The message above means: “CAPTAIN, THE DIVE BOMBER SANK THE SUBMARINE AND BATTLESHIP.”
“Two silver bars” =captain. Blue jay= the. Chicken hawk= dive bomber. Iron fish = sub. Whale= battleship. “Sheep, Axe Nose Key”=sank. The only normal use of a Navajo word is the word for “and” which is “dóó ”. For the same message the word “sank” would be spelled out another way on a different day. For example, it could be: “snake, apple, needle, kettle”.
Here, below on the video, is a verbal example of how the code sounded. The code sent below sounded to a Navajo speaker who did not know the Code like this: “sheep eyes nose deer destroy tea mouse turkey onion sick horse 362 bear”. To a trained Code Talker, he would write down: “Send demolition team to hill 362 B”. The Navajo Marine Coder Talker then would give it to someone to take the message to the proper person. It only takes a minute or so to code and decode.
