It is the only unbroken code in modern military history. It baffled the Japanese forces of WWII. It was even indecipherable to a Navajo soldier taken prisoner and tortured on Bataan. In fact, during test evaluations, Marine cryptologists said they couldn't even transcribe the language, much less decode it.
The secret code created by the Navajo Code Talkers was a surprisingly simple marvel of cryptographic innovation. It contained native terms that were associated with specialized or commonly used military language, as well as native terms that represented the letters in the alphabet.
In a simple, memorable way, the military terms tended to resemble the things with which they were associated. For example, the Navajo word for tortoise, "chay-da-gahi," meant tank, and a dive-bomber, "gini," was a "chicken hawk," (a bird which dives on its prey). Sometimes the translation was more literal, as in "besh-lo" (iron fish) which meant submarine; other times it was metaphorical, as in "ne-he-mah" (our mother), which meant America.
English words that didn't have an associated term could be spelled out using Navajo words that represented letters of the alphabet. The selection of a given term was based on the first letter of the English meaning of the Navajo word. For instance, "Wo-La-Chee" means "ant," and would represent the letter "A". Other "A" words such as "be-la-sana" (apple), or "tse-nill" (ax), would also be substituted in order to eliminate excessive repetition, which might allow the code to be cracked.
Widely acknowledged to be instrumental in the success of every major engagement of the Pacific from Guadalcanal to Okinawa, this brilliant code allowed embattled regiments of Marines to communicate quickly, concisely, and above all, securely. It saved countless lives and helped end the war.