Acoustic features of Hadza clicks

Hadza (Khoesan) has several clicks in its sound inventory [1,2]. There are 4 types of clicks in the language: bilabial, dental, alveolar and lateral [⊙, |, !, ‖] that can be accompanied, by aspirated, glottal and nasal features [⊙∼, |ʔ, |h, ŋ|, ŋ|ʔ, !ʔ, !h, ŋ!, ŋ!ʔ, ‖, ‖h, ŋ‖h, ŋ‖ʔ]. Our study was made with 9 native speakers (4 women and 5 men) using various instrumental techniques (Acoustic, aerodynamic, EGG and Video). Clicks have two components: an attack and an extinction transient. Bilabial clicks have a noisy release, sometimes whisteled. Aspiration is short for dentals and alveolars, long for laterals. Glottals have a long lag after the burst release. The 4 types of clicks can be produced with the nasal feature. Acoustically, clicks are described with 2 features [grave versus acute] and [abrupt versus noisy] [3]. The [grave] feature has a peak in the FFT spectrum around 1200Hz and the [acute] around 3000 Hz. For some clicks, the cavity posterior to the constriction is excited. Short resonances occur between 1 and 2 kHz following the posterior release, they result from the lowering of the tongue dorsum and from the reduction in the volume of the pharyngeal cavity. [1] K. Miller, Hadza Grammar Notes (Ms Riezlern, 2008). [2] B. Sands, “Phonetics and phonology: Hadza,” in The Khoesan languages, edited by R. Vössen (Routledge, London, 2013). [3] A. Traill, s“The perception of clicks in !xoo,” J. African Lang. Linguist. 15, 161–174 (1994).