Interactions between tone and voice quality in San Sebastián del Monte Mixtec modal and rearticulated vowels

San Sebastián del Monte Mixtec (henceforth SSM), also known as Tò’on Ndà’vi, is a language of the Mixtecan family, Otomanguean stock. SSM has lexical tones that are orthogonal to rearticulation on vowels. The aim of this production study is to examine both long modal and rearticulated vowels to gain insight into the SSM tonal system, contrastive voice quality, and any potential interactions between voice quality and f0. Rearticulated vowels are described as having a glottal gesture between two vowels of the same quality (V͡ˀV), while modal vowels have no such gesture (VV). To this end, we examined the phonetic realization of the lexical tones in long modal vowels in terms of f0. All tones are distinguished by f0; f0 patterns largely as expected given previously ascribed labels, with minor deviations. Secondly, the phasing and degree of glottalization in rearticulated vowels was measured using ‘strength of excitation’ (SoE); generally the glottal gesture was vowel medial with a dip in SoE at the beginning of the glottal gesture and a rise in SoE following the glottal gesture. However, there was a large degree of interspeaker variation in the production of rearticulated vowels. Additionally, lexical tone category was found to have an impact on the phasing and degree of glottal gesture in rearticulated vowels, and on voice quality in long modal vowels. This supports the idea that voice quality is an additional correlate of lexical tone in SSM.