Because of this diversity we have divided Idaho into six subregions and present the historical and ethnographic data pertinent to each area under a separate heading. Indians mentioned in the historical sources are not always easily identifiable as Shoshone, Bannock, or Northern Paiute, and a great deal of confusion between the last two is inherent in their linguistic bond. We shall use the name Bannock in its most common sense to designate the mounted, buffalo-hunting Mono-Bannock speakers of Idaho; Northern Paiute refers specifically to the Mono-Bannock population to the west of the Shoshone. In many instances we cannot be certain that the Indians encountered by one or another traveler were permanent residents of the area. Permanency, in any event, is a rather doubtful attribute of this highly nomadic people; the term cannot be used except as a designation for the people who customarily spend the winter in a certain area, and even with this limitation it must be used with caution. LINGUISTICS All of the groups discussed in this chapter except the Bannock speak the Shoshone-Comanche, or Shoshone, language. While there were only minor differences of dialect between Shoshone speakers, the Bannock language was almost identical with Northern Paiute. Informants found an especially close affinity between Bannock and the language of the Oregon Paiute, who were frequently referred to as "Bannock" also and were sometimes distinguished from the Fort Hall Bannock only by the statement that "they live in Burns" (a town in Oregon). While some informants referred to the Oregon speakers of Mono-Bannock as "Paiute," this term was generally reserved for the population of west-central Nevada, and "Pyramid Lake" was the locale in which the Idaho Shoshone generally placed the "Paiute." The inhabitants of Duck Valley Indian Reservation were not so vague; they readily distinguished between Shoshone and "Paiute" on linguistic and other grounds. This is understandable because the Shoshone had lived a long time on the same reservation as the Oregon speakers of Mono-Bannock, who were officially designated as Paiute. While no vocabularies were collected on the Fort Hall Reservation among either the Shoshone or Bannock populations, data from informants on the similarity of Paiute and Bannock more than confirm Steward's statement (1938, p. 198): The linguistic similarity of the Bannock and Northern Paiute (see vocabularies, pp. 274-275) leaves no doubt that they once formed a single group, though within historic times they have been separated by 200 miles.