The present thesis takes as its central task a structural description of Ilami verbal categories of aspect, mood, tense, and voice. By structural we mean that the assignment of a certain feature to the language under investigation is bound to whether that language employs formal devices for realising that feature. In other words, a bnguage is said to have, for example perfective aspect if that language employs separate marker for that aspect. This criterion is employed throughout the main body of the description. The main part of this description is presented in the last five sections of this thesis. A major characteristic of this work which makes it distinct from other descriptions under the general title of verbal elements, is that each one of these verbal elements are given a separate account and discussed in a separate chapter. The terminology and definitions employed in this thesis are mostly drown from bernard Comrie’s Aspect (1985) and Tense (1986).