Study On Production Of Chinese Plosives Based On Simultaneous Measurement Of Sound And Oral-nasal Airflow

Simultaneous measurement of oral and nasal airflow data during speech production is not only meaningful for examining velopharyngeal functions,but also effective to understand articulation and resonance during vowels and consonants.This is because oral and nasal airflow reflects various events during speech production,such as closure and release timing for consonants,subtle rise and fall of the velum during oral sounds,etc..Further,those events could be more detailed when high-quality speech signals were recorded simultaneously.This study is aimed at realizing such combined measurements by resolving technical difficulties for data acquisition.To do so,a nasal-oral pneumotachography system was built using an acoustically transparent mask,and it was tested by analyzing Chinese vowels and plosive consonants in speech utterances.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.