This study investigates the acoustic characteristics of /th/ lenition in conversational speech of Brunei Mandarin, a variety of Mandarin Chinese. Based on data from 20 Chinese Bruneians, /th/ lenition was found in the third-person pronoun ta /tha/, which is frequently pronounced as ha [ha]. Perceptual judgments, spectrographic analysis and acoustic measurements were conducted to examine the features of this sound change. In comparison with the perceptual judgments, it was found that the spectrographic inspection yielded 83.6% correct classification of [th] and [h] for female speakers and 77.2% for male speakers, indicating there is reasonably high reliability in identification in terms of spectral properties. Results of the acoustic measurements showed that there is an increase in high frequency intensity after the release of the closure for [th] while there is little change in intensity during the frication for [h]. The results showed that the lack of burst and little increase in intensity are reasonably reliable cues for stop lenition.
Bibliographic reference. Xu, Shufang (2014): "Acoustic investigation of /th/ lenition in brunei Mandarin", In INTERSPEECH-2014, 1974-1977.