During the Second World War, the Marine Corps Command of the United States was confronted by a difficult problem of providing secrecy of communicated messages.
All codes known at that time were broken by the enemy's specialists. The question was urgent because human life and outcome of battles depended on the encoding quality.
This situation contains an obvious contradiction.

 

• The information transfer language should be comprehensible to an American soldier (radio operator) so that he could receive and transfer information. 
• The information transfer language should not be comprehensible to an enemy so that he could not take advantage of the intercepted information.
   

An unusual solution of this problem was proposed.
There were many Indians in the US Army. A decision was taken to encode and communicate messages by using the Navajo language which was familiar only to people belonging to a certain tribe. This language is intricate and has neither alphabet nor grammar rules. Moreover, it is an unwritten language. It may be said that Navajo was an ideal language for creating a new code:

• the language existed because the Navajo spoke it 
• it did not exist for other people because no written records in this language were available.

 

At the same time, the Navajo spoke English in addition to their native tongue, that is, they could translate received information into the language comprehensible to other military men.
At the beginning of 1942, the first Navajo group arrived at the military base of Pendleton (Oceanside, California) and started work on a new code. That work resulted in the creation of a war term dictionary to be memorized by radio operators. The dictionary did not exist in writing.
After taking a special training course, a Navajo radio operator was usually sent to a Marine Corps troops operating from the Pacific war theatre. His chief duties were transfer of battle information and orders by telephone and radio, but he also took part in battles as an ordinary soldier. The feature film 'Windtalkers' by John Woo (2002) gives a detailed and trustworthy account of those events.
The code based on the Navajo language did not become less valuable after the war, either. Due to that, the code and the names of Navajo code-talkers were kept classified. Only a short time ago, the Navajo code-talker whose courage and skill saved thousands of lives and made a significant contribution to the victory in that war received recognition from the Government and society.
 

Here are the basic principles of the Navajo code.
A Navajo code-talker received a message in his native language. The message comprised a string of unconnected words.
Each word was translated into English.
Then the first letter of the English equivalent of this word was taken, for example, “vol-la-chi” (ant), “be-la-sana” (apple), “tse-nill” (axe) meant the letter "a".
To say “navy”, a code-talker had to communicate the following message:
tsa > Niddle
vol-la-chi > Ant
a-ke-di-l'ini > Victor
tsa-a-tsoh > Yucca
 

For more detail see: www.simonsingh.net
www.library.thinkquest.org
www.lapahie.com.
Images: www.simonsingh.net
www.texancultures.utsa.edu.