The correct answer is as code talkers in the Pacific.
During World War II, the American military needed to communicate secretly without the Axis powers being able to interpret their message. The American military then turned to the Navajo tribe, as they have an extremely complex language that was difficult to break. The Navajo code talkers were able to communicate important battlefield messages (ex. quickly describe where the enemy troops are and how far they are away) in several different battles in the Pacific theatre. This group would share thousands of messages over the course of World War II.
