Code talkers:
Code talkers were the person appointed or employed during the wartime by the US Marine Corps. The duty of the code taker is to learn and utilize the little known language to make it as the means of secret communication.
They are majorly the bilingual Navajo speakers. This technique was pioneered by Choctaw or Cherokee people during the time of world war I. Approximately, 400 to 500 Native Americans were involved in this job during that period.