Articulatory and acoustic investigations into gestures of Mandarin retroflex fricatives Free

This study investigates the inventory and acoustic realizations of articulatory gestures of the Mandarin retroflex (or arguably, post-alveolar) fricative /ʂ/. Tongue shapes were obtained with ultrasound images and categorized as retroflexed or bunched, in light of the literature on the North American English rhotic /ɹ/ production. Velarization, a secondary articulatory gesture of retroflex consonants, was also coded in the ultrasound imaging analysis. Lip rounding, found to be an optional enhancing gesture in Mandarin retroflexion, was identified with lip video data. The acoustic measurements included the spectral center of gravity obtained from the middle of the frication and F2 frequency measured at the onset of the vowel following the fricative. The analyses showed that the spectral center of gravity only varied as a function of the vowel context. F2 at vowel onset was affected by vowel context, velarization and the interaction of vowel context and lip rounding. The preliminary results failed to support previous speculations that the two tongue shapes in Mandarin retroflexes result in different acoustics. We consider including more acoustic measures to further explore the acoustic consequences of articulatory variations in Mandarin retroflex fricatives.