Acoustic characteristics of Xhosa clicks

Xhosa, a Bantu language of Southern Africa, has 15 distinct clicks. Clicks are made at three places of articulation—dental, alveo-palatal, and lateral—and with five different accompaniments—voiceless, aspirated, nasalized, murmured, and nasalized murmured. A recording was made of eight speakers saying words containing each of these 15 clicks before each of the five vowels /i,e,a,o,u/. The DSP Sona-Graph was used to produce wideband spectrograms, waveforms, and spectra of these utterances. Dental clicks were marked by fricative noise occurring throughout a wide frequency range, and by lack of a clear onset. Alveo-palatal clicks were marked by an abrupt release with little frication. Lateral clicks were more affricated than the alveo-palatal clicks. The place of articulation of the click was not observed to have any effect on the formant transitions of the following vowel. Observed vowel effects on clicks were limited to the reduction in amplitude of high-frequency noise before rounded vowels /u/ and /o/. The five accompaniments at each place have a number of phonetic characteristics that will be discussed. [Work supported by NSF.]