Individual variation of morphological and acoustic effects of the nasal tract

Previous studies have reported that nasal consonants in Mandarin are an important source of individual information. This study conducts morphological analysis and acoustic modeling of the nasal and paranasal cavities to investigate the effects of the nasal cavity on speaker characteristics. Morphological analysis was carried out on the perpendicular planes to the nasal tract and the cross-sectional area functions of the nasal tract based on volumetric MRI data obtained for four Chinese speakers. It was shown that the nasal cavity possesses relatively large variation across speakers. Furthermore, acoustic effects of the individual variation of the nasal cavity were estimated by using a transmission line model. The results showed that the interspeaker variation of the nasal tract affects spectra in the frequency range from 2 kHz to 4 kHz, which is in agreement with the results from our previous statistical studies.