I just finished a book called "Navajo Code Talkers" by Nathaan Aaseeng.  It's the story of how the Indians help the US win WWII.  

The idea for the code talkers began with a man who as a child of missionaries, learned the Navajo lauguage. Armies are always trying to break the code of the enemy.   Since the Navajo language is only a spoken one, there was no written records.  Enlisting the talkers into the Marines, enabled the commanders to direct their units without the Japs being able to learn any information from the messages.  

Code tallkers were successfully used in th Guadalcanal  campaign as well as the Iwo Jima and Okinawa campaign.  

After the war their efforts were classified material and for many years the story could not be told.  Now most if not all of the Code Talkers are dead, and thier efforts have make them heros. After fifty-eight years, Congress enacted legislation awarding the Congressional Gold Medal and the Congresaional Silver Medal to this select group of Amricans.