一至六歲兒童的國語塞音習得與發展

Abstract

本研究的主題是一歲到六歲兒童的國語塞音習得與發展。這項發展採用聲音起始時間 (voice onset time, VOT) 來衡量並記錄塞音的送氣時間。 一歲兒童的發展結果分別從一歲六個月和一歲八個月大的幼童觀察而來。為期約五個月的觀察結果顯示其中一位兒童已經習得雙唇和舌尖塞音的送氣與不送氣區別，而另一位尚未習得。同時也發現二位兒童的送氣時間變化的模式有些相似，儘管仍有相當大的個人差異。首先，所有塞音的送氣時間都較短；較長的送氣時間在後來才發展出來。這種發展的順序可能是由於喉嚨與發音的協調程度不一所導致。 二歲到六歲的兒童都已經習得雙唇、舌尖、和舌根三組塞音的送氣與不送氣區別。但是，這些兒童所發出的塞音當中，送氣的時間仍有顯著性的差異。三歲幼童的送氣時間很明顯的比大部分其他年齡的幼童還短，這可能是發音矯枉過正所產生的結果。五歲和六歲孩童的塞音送氣時間和大人的很相似。各個年齡之間的送氣時間變化可能顯示了孩童藉著不斷調整送氣的程度，以符合大人的發音模式。各年齡孩童的送氣變化也證明了語言發展是傾斜改變 (gradient change) 的過程。本研究所提供的跨越了六個年齡層的大規模紀錄和觀察可以當作語言治療的參考。

This study provides empirical data of the development of Mandarin aspiration contrast from a longitudinal and a cross-sectional perspective. Voice onset time (VOT) is employed to measure the progress of aspiration contrast which is characteristic of labial, dental, and velar stop consonants. The longitudinal study recorded two children’s speech production at approximately every two weeks, beginning when they were about 1;8 and 1;6 respectively. Results showed that one of the subjects has acquired aspiration contrast between homorganic labial and dental stops while the other child has not when the study ended. It was also found that overall both of the two subjects exhibited similar pattern of VOT variation in the process of the development though great individual differences often existed between the two children. They seemed to produce all of the stops with shorter VOT values in the beginning of the study. Longer VOT values appeared to develop at a later time. It was speculated that the sequential order of acquisition and development of aspiration contrast can be resulted from different degrees of the coordination between the laryngeal gesture and the point of articulation. On the other hand the cross-sectional study examined the development of the aspiration contrast from two- to six-year-old children. Each group of children has acquired aspiration contrast but mean VOTs were found to be significantly different in all of the three aspirated stops and the unaspirated velar stop. The mean VOTs produced by three-year-olds were found to be shorter than most of the other groups, suggesting over-performance on the control of aspiration feature. The mean VOTs produced by the oldest two groups better resembled those in the adult group. It was assumed that the distinctions of VOT values among child groups could be attributed to children’s persistent attempts to adapt their VOT values to approaching the adult norm. The continuous VOT variations across the five groups of children also added evidence to gradient change in language production, especially in the aspect of aspiration contrast. In addition with the detailed documentation and observation of VOT values from a wide range of age this study also provided some reference for speech therapy.