廣州話元音發音與聲學之關係

Articulatory–Acoustical Relationship in Cantonese Vowels

本文分析廣州話兩組邊緣元音[1: u: a:]和[i u a]的發音與聲學之關係。長元音[1: u: a:]在CV開音節中出現；[i u a]在CVC閉音節中時長縮短。根據兩男和兩女發音人的舌位及共振峰資料顯示，(i)相對於長高元音[i: u:]，縮短了的高元音[i u]的共振峰在聲學元音區域中不達目標，同時[u]在發音元音區域中也不達目標；不過，(ii)這種時長對高元音[i u]的影響，在低元音[a]中沒有產生。有關元音的發音與聲學關係方面，(i) [i: u: a:]和[i u a]的F1及F2共振峰，對於舌頭與上顎間收窄點的x（前後）位置及y（上下）位置移位的敏感度屬低，這表示廣州話的邊緣元音具有quantal的性質；及(ii)邊緣元音 [i: u:]，而非[a:]及[i u a]，其F1及F2共振峰對於舌頭與上顎間收窄點的x位置移位的敏感度，比對y位置移位的敏感度為低，這表示(a)低邊緣元音的quantal性質的程度比高邊緣元音的為低，及(b)縮短了的邊緣元音的quantal性質的程度比長邊緣元音的為低。本文的分析結果跟相關的語音學理論作討論，如元音目標減縮理論及quantal理論，也與英語中邊緣元音的發音與聲學關係作比較。

This paper investigates the articulatory–acoustical relationship in the production of the Cantonese long point vowels [i: u: a:] in CV syllables and shortened equivalents [i u a] in checked CVC syllables, through an analysis of the tongue positions and corresponding formant frequencies for the vowels. The articulatory and acoustical data from four Cantonese speakers, two male and two female, show that: (i) the shortened high vowels [i] and [u], relative to the long [i:] and [u:], undergo formant undershoot in the acoustical vowel space and [u] also undergoes target reduction in the articulatory vowel space, and (ii) the effect of shortened vowel duration is not observed in the low [a]. The data on the articulatory–acoustical relationship show that: (i) the levels of sensitivity of F1 and F2 to the variations in tongue displacement are low in each of the vowels [i: u: a:] and [i u a], suggesting that the Cantonese point vowels are quantal, and (ii) the sensitivity of the formant frequencies is lower to the variation in tongue constriction in the x-dimensi on than in the y-dimension in the long [i: u:], but not the long [a:] and shortened [i u a]. This suggests that: (a) the low vowels are less quantal than the high vowels and (b) the shortened vowels are less quantal than the long equivalents. The results are discussed in connection with the theory of vowel target reduction, the quantal theory, and the articulatory–acoustical relationship in the English point vowels.