Differences in airstream and posterior place of articulation among Nuu clicks

This paper describes the consonant inventory of the endangered southern African language Nuu. Our novel approach to segment classification accounts for all 73 Nuu consonants with just four phonetic dimensions (place, manner, phonation, airstream) and does away with the phonetically empty category click accompaniment. We provide ultrasound data showing that the posterior constrictions in clicks are not produced at the velar place of articulation, and that posterior place differs with anterior place. We therefore argue for a terminological shift from velaric to lingual airstream mechanism. Our data also show that the posterior place of articulation is the same in Nuu's five lingual ([⊙|! ∥ ‡ ]) and linguo-pulmonic ([⊙q|q!q∥q ‡q]) stops. We argue that the difference between these segment classes is best captured in terms of airstream, not place. Plain clicks use only the lingual airstream, while linguo-pulmonic segments are airstream contours, in which the transition to the pulmonic airstream occurs within the segment rather than at its boundary. Our evidence suggests that the contrast between velar and uvular clicks proposed for the related language X is likely also one of airstream and that a contrast solely in terms of posterior place would be articulatorily impossible.