Sentence:  bursting from the lips of a charging cavalry trooper was the last sound heard on this earth by untold numbers of Cheyennes , <WSD>Sioux</WSD> and Apaches , Mexican banditos under Pancho Villa , Japanese in the South Pacific , and Chinese and North Korean Communists in Korea . 
Meaning of the word marked with <WSD> tags:  a member of a group of North American Indian peoples who spoke a Siouan language and who ranged from Lake Michigan to the Rocky Mountains