Acoustic analysis of the vowel system of Yongding Hakka Chinese

The paper is an acoustic analysis of the formant frequencies and durations of the two sets of Yongding Hakka vowels, [i a i] in CV syllables and [i? a? u? ε? c?] in CVS syllables, from 10 male and 10 female speakers. The formant data show that the Yongding Hakka [i] has the F-pattern of a mid central, rather than a high central, vowel, and the vowel [i?] has the F-pattern of [I?]. The durations of [i? a? u? ε? c?] are about half of those of [i a i]. While shortened duration brings about vowel reduction and formant undershoot in [i?] relative to [i], no apparent change in F-pattern is observable in [a?] compared to [a]. The Yongding Hakka vowels [i i] and [i? u? ε? c?], excepting [a] and [a?], have large between-vowel-category dispersion in the F1F2 plane, with no or minimum overlaps between any vowels. A larger vowel loop area for [i? a? u? ε? c?] than [i a i] supports the general expansion effect with respect to vowel inventory size as claimed by the vowel dispersion theory. A smaller Euclidean distance to the gravity center of the acoustical vowel space for [i? a? u? ε? c?] than [i a i] agrees with the target undershoot model which predicts reduction and formant undershoot in vowels of shortened duration.