Windtalkers

Windtalkers is a movie starring Nicolas Cage, Adam Beach, and Peter Stormare. Two U.S. Marines in World War II are assigned to protect Navajo Marines, who use their native language as an unbreakable radio cypher.
Joe Enders is a gung-ho Marine assigned to protect a "windtalker" - one of several Navajo Indians who were used to relay messages during World War II because their spoken language was indecipherable to Japanese code breakers.