The Choctaw (Chahta), Comanche (Numinu), Hopi, Cherokee (Aniyunwiya), and Navajo (Dine) served in the US military as code talkers in WWI and WWII. By the end of WWI 25% of the Native American male population were actively serving in the military. Today we honor all Veterans of the United States Military.
http://blog.nativepartnership.org/honoring-native-veterans-on-national-code-talkers-day/