粵語音節延長對韻腹韻尾時長的影響

粵語音節時長的相對固定，跟粵語在特定情況下個別音節須要延長，兩者之間不但並無矛盾，還是相輔相成的。音節延長的理由不一，其中一個理由是用以體現句子重讀。本文主要通過比較非重讀音節與重讀（意味延長）音節的時長表現，審視粵語音節的延長對韻腹韻尾時長有怎樣的影響。

本文所據的實驗有一男一女兩個發音合作人，實驗分成兩部分。第一部分看元音尾、鼻音尾、塞音尾三種韻母類型的音節在被延長時韻腹韻尾時長比例的變化。結果顯示，除了短腹長塞尾的情況外，其餘五種情況都劃一地把延長音節的任務主要由原來就屬長的韻腹或韻尾來擔負；但短腹長塞尾類型的韻母則與別不同地主要把自身屬短型的韻腹來拉長。

第二部分實驗集中看在第一部分表現異常的塞尾韻，用窮盡性的後接聲母搭配去擴大樣本，進一步檢視[a:t]、[ɐt]兩韻（分別代表長腹和短腹兩種類型）的不同表現。結果顯示，女合作人的表現完全符合第一部分的表現；男合作人則有點反覆：大部分情況與女合作人的情況細節不同而大體相類，但不論長腹韻或短腹韻，都有小部分情況表現異常，未有明顯的規律性。女合作人的全部表現和那佔男合作人大部分情況的相類表現，基本符合我們對粵語母語者一般表現的覲察。我們可以假定這就是粵語母語者的正常表現。在這種表現之下，粵語短腹塞尾型韻「主要通過延長本來屬短型的韻腹去延長音節」這異於其他韻類的現象，可從塞尾本身體現為語音空白因而不宜拉長而得到解釋。

Syllable isochrony in general and motivated syllable lengthening at times in Cantonese are no contradiction; in fact they corroborate each other. Signaling of sentence stress is one of the functions that syllable lengthening fulfils in Cantonese. This paper compares the duration structures of stressed (therefore lengthened) and non-stressed syllables, so as to see the effect of syllable lengthening on the duration of the syllable nucleus (V) vis-a-vis that of the coda (Cd).

The paper is based on an experiment with two informants, one male (M) and one female (F). The experiment has two parts. Part 1 looks at how the trochaic (long V, short Cd) rimes and iambic (short V, long Cd) rimes behave, respectively, across the three types of rimes classified according to manner of articulation of coda, namely, vowel vs. nasal vs. stop. The results show that, with the exception of iambic rimes with stop coda, all the other five types of V-Cd configuration exhibit the pattern of putting the burden of lengthening mainly on the part (V or Cd) that has the "long" attribute. Iambic rimes with stop coda, on the other hand, put that burden mainly on the V, which originally has the "short" attribute.

Part 2 is focused on rimes with stop coda, which show anomaly in Part 1. The rimes [a:t] and [ɐt](representing trochee and iamb respectively) combine with different following onsets exhaustively to give a larger sample. The results corroborate the pattern exhibited in Part 1 as far as F is concerned. As for M, the results are somewhat mixed. While the majority cases are compatible with F, the remainder cases (applicable to trochaic and iambic rimes alike) are disparate and defy clear pattern abstraction. The pattern that F exhibits throughout and M exhibits in the majority of cases corroborates our observation of the general behavior of native speakers of Cantonese. One can assume that this is the normal behavior of native Cantonese speakers. In this behavior, the singular pattern applicable to iambic rimes with stop coda, namely that it is mainly the V with the "short" attribute that is lengthened to achieve syllable lengthening, can be explained by the fact that a stop coda in Cantonese typically assumes a period of time without audible phonetic signal, and thus does not lend itself to lengthening. Copyright © 2010 香港中文大學出版社.