de Reuse This project consists of linguistic fieldwork to be carried out on Western Apache, a Southern Athabaskan language spoken on the four present-day Apache reservations and communities of Arizona (San Carlos, Fort Apache, Payson (Tonto-Apache), and Camp Verde (Yavapai- Apache)). The fieldwork will lead to a reference grammar of the Western Apache (WA) language, with particular attention to dialectal variation, and containing illustrative morphologically analyzed texts in various dialects. An attempt to document the remnants of the Chiricahua Apache language on these Apache reservations will also be made, if speakers can be located. The resulting reference grammar of the Western Apache language will contribute to the field of descriptive linguistics by providing documentation of this typologically interesting language. It will emphasize points of current theoretical interest, such as: underlying representations in tonal languages; the derivation of the linear ordering of morphemes and the need for position class morphology; and the function of the yi-/bi- alternation and its interaction with definiteness and specificity. It will also contribute to comparative and historical Athabaskan, especially in view of the fact that WA has phonological peculiarities reminiscent of the Northern Athabaskan languages of Canada, which do not occur in Navajo, its closest Southern Athabaskan relative. Finally, this work will be relevant to theoretical work on variation intralinguistically (i.e. variation within the WA language) and interlinguistically (i.e. when WA is compared to other Athabaskan languages).