Luo Tonal Structure: A Phonetic and Phonological Analysis

Abstract

This paper presents a phonetic and phonological analysis of tonal patterns in Luo, a Western Nilotic language spoken primarily in Kenya and Tanzania. The paper mainly focuses on the classification and representation of lexical and grammatical tones. Drawing on field data, the paper establishes that Luo has four lexical tones—two level tones (High and Low) and two contour tones (Falling and Rising). It also identifies two melodic tonal patterns, HHH and LHLL, for grammatical tones. While level tones show subtle pitch distinctions, consistent with two-tone systems, contour tones appear in both simple and complex forms. The paper adopts Autosegmental Metrical (AM)Theory to account for tonal behaviours, in support of the view that contours in African languages are sequences of level tones that combine to form contour tones. From this perspective, the study concludes that since Luo contrasts two-level tones, it has only two underlying contour tones: HL and LH. Other tonal configurations are surface-level effects. Acoustic evidence also reveals that L tones may exhibit a slight fall, which is attributed to a production effect. Generally, the study concludes that Luo tones are phonologically governed, with AM theory offering a coherent model for explaining the tonal association and contour formation.