licks, i.e.. âvelarically initiated, ingressive suc- tion sto p ... sounds in JIPA (Simpson,. 2013), studying clicks is ... aud ito ry detection and description of the sounds.
What are the relevant acoustic characteristics and dimensions that distinguish clicks at different places of articulation?
Do clicks vary along their relevant acoustic dimensions in different segmental and prosodic contexts?
Given that clicks result from complex coordinated movements of two active articulators and are essentially characterized by their burst and fricative elements, are clicks also subject to speech reduction (→ assimilation, lenition), just like pulmonic stop consonants?
Our study aims at supporting a complementary line of research on the instrumental measurement of clicks, as in Simpson (2007), Fuchs et al. (2007) and Fuchs & Rodgers (2013). With a stronger focus on comparative, context related analyses of acoustic details, we are concerned with the following phonetic-phonological questions :
• Clicks, i.e. “velarically initiated, ingressive suction stops” (Ogden, 2009), are of growing interest in the speech sciences. • They are an understudied phenomenon, particularly with respect to their phonetic exponents and variability. • Clicks are typically associated with “exotic” African languages like ǃXóõ, Khoekhoegowab, and Zulu, as they are phonologically contrastive here. ↔ A new line of research showed that clicks are also anything but absent from European languages, although they occur here only non-phonemically and with different speaker-specific frequencies. • But, even in this new line of research, whose importance has recently been stressed by a special issue on non-pulmomic sounds in JIPA (Simpson, 2013), studying clicks is mainly limited to functional analyses based on an auditory detection and description of the sounds.
1 . Introduction Andriesvale
• We investigated the acoustic variation of clicks, as induced by stress-level induced degrees of speech reduction. • The level of sentence stress of the syllables containing the clicks was labeled perceptually by means of the 4-step PROLAB system (Kohler, 1997). • The clicks were analyzed in PRAAT with respect to • (A) total duration, • (B) number of release bursts, • (C) temporal distance between the bursts. • Click-related fricative sections were additionally analyzed in terms of • (D) mean energy level, • (E) lower spectral energy boundary, • (F) number of spectral peaks (“spectral waviness”), • (G) frequency of spectral energy maximum, • (H) the center of gravity (CoG), • (I) skewness of the CoG.
Olifantshoek • Nñuu is the last living member Upington Raaswater of the ǃUi langauge family. • Nñuu is a moribund language • …currently spoken by less than 10 elderly individuals in West South Africa. • The present analysis are based on a corpus of spontaneous Nñuu (Güldemann et al. 2007-2011). • Our speech sample includes by now a total of 100 click-phoneme realizations that occurred in prosodically controlled contexts, i.e. at the onset of mono- or disyllabic high-frequency nouns and verbs, balanced across phrase-initial, -medial, and -final occurrences: • 20 bilabial clicks (/áoe/ ‘meat’) • 25 dental clicks (ñaeki/ ‘woman’) • 18 alveolar clicks (/!uu/ ‛person’) • 17 palatal clicks (/úoo/ ‘man’) • 20 lateral clicks (/Ñaaxe/ ‛sibling’)
2 . Method
• MANOVA: • “Click Type” has a significant effect on all temporal and spectral acoustic parameters (0.05>p>0.001), except for skewness; and parameter differences vary between compared types of clicks. • Significant interactions “Stress Level” * “Click Type” for some temporal and spectral parameters → [á] and [ñ] vary more than [Ñ] and [ó] under changes of stress.
• Discriminant analysis: Significant discrimination of “Click Type”: Functions 1 & 2 (pPAL>LAT>ALV(low) • Distinguishing clicks by their “Stress Level” is more difficult, yet possible → variation → points to reduction. • Different click types/contrasts differ along different phonetic parameters and are differently susceptible to effects of reduction and prosodic context. • Reduction of clicks is possible, but total reduction is rare → qualitative difference between the reduction potentials of clicks and pulmonic stop consonants. • Further questions: (1) Place assimilation of clicks? (→ no information due to the phonotactics of Nǀuu); (2) Generalization of findings to other click languages?
4 . Discussion & Conclusion
Example of a reduced bilabial click in /áoe/ (‘meat’)
Example of a reduced alveolar click in /!uu/ (‘person’)
Acoustic characteristics and variation of clicks in the endangered language Nǀuu
