Measuring oral and nasal airflow in production of Chinese plosive

This study reports a new integrated device for measuring oral and nasal airflow with lossless speech recording with preliminary results on Chinese plosives. An acoustically transparent fiber-made mask acts both as a material for airflow resistance and a support for partitioning oral and nasal chambers. Two pressure sensors placed directly on the mask measure air pressure signals that correspond to the airflow rate. With this device, oral-nasal airflow rate and speech sound were recorded from two Chinese speakers. The corpus was made of two-syllable Chinese words (CVCV, C is a plosive) in a carrier sentence. Slow and rapid variations of nasal airflow signals were obtained with clear speech and oral airflow data, which were analyzed to speculate the elevation and vibration of the velum. The results show that (i) AC component of the nasal airflow is greater in /i/ than in /a/, which supports transvelar nasal coupling during high vowels and obstruents; (ii) word-medial plosives tend to be partially or fully voiced, as inferred from augmented AC amplitude of the nasal airflow during the closure; (iii) short rise or drop of the nasal airflow appears to reflect a quick elevation or decline of the velum.