An acoustic study of contrasting plosives and click accompaniments in Xhosa

The phonetic manifestation of distinctive plosive types and click accompaniments in Xhosa was investigated with measurements of voice onset time (VOT), closure duration, voicing during closure, and burst amplitude. There is a high degree of interspeaker as well as token-to-token variability in the voiceless unaspirated plosives and clicks concerning their pronunciation with or without audible ejection. The plosives are much more frequently ejective than the corresponding clicks. If present, ejection is manifested by increased VOT, burst amplitude, or both. Duration of voicing during closure is substantial only in the implosive, but not in the 'voiced' plosives and clicks. After nasals the percentage of voicing during closure is high in 'voiced' plosives due to the very short closure duration found in that context; in the post-nasal 'voiced' clicks closure is mostly reduced to zero. Aspirated plosives and clicks in Xhosa show VOT values that are on average relatively long when compared to other languages. Closure duration tends to be shorter in aspirated plosives and clicks than in other categories.