Koyukon is an Athabaskan language spoken along the Yukon and Koyukuk rivers in Alaska. Even among the Athabaskan languages, which are noted for the richness of their aspectual inventories and the diversity of expression possible from these inventories, Koyukon has the most elaborate and richly varied possibilities of morphologically marked derivational aspect. (Aspect is the nature of the action of a verb as to its beginning, duration, completion, or repetition and without referenced to its position in time, and the set of inflected verb forms that indicate aspect).
The work consists of three parts: an examination of the aspectual system, which involved sorting out a complex network of four modes, fifteen aspects, four superaspects, and some 300 aspect-dependent derivational prefix strings; an analysis of the organization of verb-theme categories, which are directly linked to aspectual categories; and an assessment of the function of the aspectual system as a whole.
