An analysis of tone in language begins with the observation that the structural approach taken in segmental phonology, analyzing complex tones in terms of sequences of level tones, is not necessarily appropriate with tone languages. A different approach is proposed, a "dynamic-tone" theory that represents tone contours entirely in terms of two "tone markers" representing rising and falling pitch. This theory is offered as a universal theory of tone. The first three chapters outline the way in which the theory accounts for a wide variety of tonal phenomena, including pitch-accent language, tone languages, and phrasal tone. The fourth chapter, concerned with the nature of and constraints on tone rules, describes how tone rules may be confined to three processes: insertion, movement, and deletion of a tone marker. Chapter 5 addresses a number of issues, including tonal stability and the theory of gliding tones. The sixth and seventh chapters contain detailed analysis of the tonal system of Igbo, with particular attention to the specification of syntactic environments for its major tonal processes. In chapter 8, the interaction between phonology and syntax is examined, and a specific constraint is proposed. (Contains 68 references.) (MSE)