Dispersion and variability of vowels of different inventory sizes

This study investigates dispersion and variability in the vowels of systems with different phonemic inventory sizes in three Chinese dialects. Yongding Hakka, Hong Kong Cantonese, and Wenling Wu have three, seven, and eleven vowel phonemes, respectively. Measurements of formant frequencies were obtained through a spectral analysis of speech data from twenty male and twenty female speakers of each dialect. Results show that the size of acoustical vowel space in the F1F2 plane increases with an increase in vowel inventory size. The finding supports the vowel dispersion theory (Lindblom, 1968; Liljencrants and Lindblom, 1972) which claims that the larger the inventory is, the more expanded the vowel space will be. However, the prediction by the theory that variability in vowel formants is inversely related to the vowel inventory size is not supported by the vowel formant data from the three Chinese dialects. In Fant (1966, 1975), female vowels are said to exhibit greater between-category dispersion in the F1F2 plane than male vowels. The observation is supported by the vowel formant data from the three Chinese dialects. However, this is true before vowel normalization, but not after. Lastly, no gender-related patterning of vowel dispersion is observed in the three Chinese dialects.