Abstract:

Individual difference of the orofacial structure and its articulatory and acoustic influences have been studied based on the University of Wisconsin x-ray microbeam database [Honda and Wu, J. Acoust. Soc. Am. 100, 2598(A) (1996)]. This work describes a subsequent statistical analysis on the same datasets. The outlines of the orofacial structure of 20 subjects (10 Japanese and 10 English speakers) were extracted from lateral x-ray scan images and mapped onto a midsagittal reference space defined by the palatal plane and anterior nasal spine. Vowel records in the microbeam data were analyzed to reveal the effect of orofacial morphological difference on vowel articulation and acoustic parameters. In the main results, the size parameters were commonly correlated with the three formant frequencies. In particular, the lower facial height or the size of the mandibular symphysis showed a clear tendency to inversely correlate with the first formant. Among the parameters of form, oral cavity aspect ratio and mandibular symphysis shape thought to be possible factors affecting vowel gestures, which were reflected in the spread of the second formant in all the vowels analyzed. A multiple regression model of speaker characteristics will be discussed.