A laryngographic and laryngoscopic study of Northern Vietnamese tones.

A laryngographic and laryngoscopic study of tone production in Northern Vietnamese, a language whose tones combine both fundamental frequency (f0) modulations and voice qualities (phonation types), was conducted with 5 male and 5 female speakers. Results show that the f0 contours of Northern Vietnamese tones are not only attributable to changes in vocal fold length and tension (partly through changes in larynx height), but that f0 drops are also largely caused by the glottal configurations responsible for the contrastive voice qualities associated with some of the tones. We also find that voice quality contrasts are mostly due to glottal constriction: they occasionally involve additional ventricular fold incursion and epiglottal constriction, but these articulations are usually absent.