Navajo was the perfect choice for a secret language. It is very complex. One vowel (元音）can have up to ten different pronunciations, changing the meaning of any word. In the 1940s, Navajo was unwritten language. No one outside of the reservation could speak it or understand it.

    The Navajo Code team had to invent new words to describe military equipment. For example, they named ships after fish: lotso-whale (battleship), calo-shark (destroyer), beshloiron-fish (submarine). When a Code Talker received a message via radio, he heard a series of unrelated Navajo words. He would then translate the words into English and use the first letter of each English word to spell the message. The Navajo words tsah (needle), wol-la-chee (ant), ah-kh-di-glini (victor), and tsah-ah-dzoh (yucca) spelled NAVY.

    The Code Talker kept the code a secret. They memorized everything. There were no code books. As a result, no ordinary Navajo soldiers, if captured by the enemy, could understand the code. More than 3,600 Navajos served in World War II, but only 420 were Code Talkers with the US Marines. They coded and decoded battlefield messages better and faster than any machine. They could encode, transmit, and decode a three-line English message in 20 seconds. Machines of the time required 30 minutes to perform the same job.

    Even after the war the code remained top secret. When they were asked about their role, Code Talkers just said: “I was a radioman.” War movies and histories came out without mentioning them. The code was never used again and was finally declassified in 1968. Only then did the secret came out.