Tone Shift and Tone Spread in siSwati: An Alignment Approach
Mobility of High (H) tone is one of the fundamental phenomena of Bantu tonology (Kisseberth & Odden 2003: 62). H tone shift and H tone spread are instances of such mobility. This paper discusses tonal behaviour in siSwati (S.43) within the framework of Optimality Theory. In siSwati, H tone moves rightwards, to the penult in phrase-medial forms and to the antepenult in phrase-final forms. The generalisation that tone moves rightwards is accounted for by an alignment constraint, ALIGN-R, which requires that H tone be aligned with the right edge of the word. To account for the extratonality of the final syllable(s) I use the constraint NONFINALITY. However, monosyllabic and disyllabic roots behave differently from polysyllabic roots because they realise tone on the final syllable. Since movement is only rightwards, leftward movement is blocked by the constraint ANCHOR-L which requires that the left edge of the tone in the output should correspond to a left edge in the input.