Phonetic implementation of high-tone spans in Luganda

Abstract

In Luganda, a Bantu language of Uganda, there are long high-tone spans, which include multiple syllables, as well as short high-tone spans, limited to a single syllable. Long high-tone spans result from unbounded leftward spread of either lexical high tones or an intonational high boundary tone. This study investigates whether long tone spans in Luganda differ phonetically in f₀ timing or scaling from short tone spans, and whether lexical high tones are implemented differently than intonational ones. In a production study involving 10 Luganda speakers, it was found that the initial f₀ rise ends significantly later in long high-tone spans than in short high-tone spans, reflecting the reduced time pressures involved when the f₀ rise is in a separate syllable than the f₀ fall. The final f₀ fall at the end of the span begins earlier in the syllable in long high-tone spans than in short high-tone spans, reflecting the same time pressures. There was no difference in f₀ level between long and short high-tone spans, indicating that the time pressure does not lead to undershoot. The intonational high tone has significantly smaller f₀ excursions in the initial rise and the final fall, compared to the lexical high tones.