The thesis treats of pitch features of Riyadhi Colloquial Arabic in terms of thirteen tones, ten "finals" and three "medials", an exponent of any of these being termed a "tone group". The distinction between final and medial here was based upon the fact that members of the former may occur both singly and in combination, whereas members of the medial type do not occur singly. Differentiation between one final tone and another was based upon contrastive pitch features coupled with parallel situational ones. Grammatically similar utterances were found to stand in functional contrast to each other on account of their being associated with contrastive, tono-situational features. Although the function was assigned to the tone group, or combination of tone groups, as a single indivisible unit, it was realized that no thorough comparison, ". or indeed a clear one, could be made between the various tones unless their multiplicity of patterns were first to be reduced to elements of tonal structure common to each and every one of them. These were established as: pretonic and tonic, the latter subsequently subdivided into tonic syllable and tonic extension. Because tone groups occurred singly and in combination and because the latter consisted of varying numbers and various types of components, it was necessary to establish a higher unit of structure, the contour. And in order to account for the very apparent characteristics of spontaneous speech (viz. hesitation, interruption, repetition etc. ) the contour was subdivided into "complete", "incomplete" and "interrupted". The function of the complete contours was then studied in association with "single tone groups" and "combination of tone groups". Finally the perceptual and instrumental observations upon which the analysis was based were supported by some spectrographic evidence. Because of the poor quality of the original recordings from which the spectrographic tracings were made, this evidence was given in a separate appendix.