Dispersion and Variability of Male and Female Vowels - Data from Three Chinese Dialects

Vowel is a subject which has attracted much interest and attention of phoneticians over many decades. This research explores two theoretical issues of acoustic realization of vowels in the Chinese context: (a) vowel dispersion and vowel variability; and (b) relativeness of male and female vowels. The Chinese dialects selected for the study are Yongding 永定話 of Kejia 客家 family, Changsha 長沙話 of Xiang 湘 family, and Wenling 溫嶺話 of Wu 吳 family, which differ in vowel inventory size. Yongding has a vowel system of three vowel phonemes and Wenling a system of eleven, which are the smallest and largest vowel systems in Chinese, while Changsha has a vowel system of seven which is the most frequent vowel system (Zee and Lee, 2007).The vowel dispersion theory which is based on the principles of 'maximal perceptual contrasts' (Liljencrants and Lindblom, 1972) and 'sufficient perceptual contrasts' (Lindblom, 1986) claims that the vowels of a given language are arranged in the F1F2 acoustic plane so as to minimize the potential for perceptual confusion between distinct vowel categories. Two interpretations for the theory are: (a) the acoustic realization of vowel categories depends on vowel inventory size; and (b) variability of individual vowels is inversely related to vowel inventory size. This research investigates the effect of vowel inventory size on: (a) dispersion of vowel categories in the F1F2 acoustic plane in Yongding, Changsha, and Wenling; and (b) degree of variability for the vowels of each of the dialects.Female vowels are known to have higher formant frequencies than male vowels. Fant (1966) attributes this to a longer vocal tract for males than females and a greater ratio of pharynx length to the overall vocal tract length for males than females. This research determines: (a) the scaling between male and female vowel formant frequencies across vowel categories for Yongding, Changsha, and Wenling; (b) whether female vowels exhibit greater between-category dispersion in the F1F2 plane than male vowels for the three dialects; and (c) the effect of vowel inventory size on (a) and (b).The study is expected: (a) to make available corpora of formant frequencies of the vowels of Yongding, Changsha, and Wenling to future investigators of acoustic characteristics of the vowels of Chinese; and (b) to contribute to discussions in the literature of vowel dispersion theory and male-female differences in spectral realization of vowel categories with data and evidence from Chinese.