当音节的时程长于60毫秒时,普通话中6个单元音的识别率一直保持在95％以上的水平。当音节的时程短于60毫秒时,元音识别率随时程的缩短而逐渐下降。当音节短至8—13毫秒时,元音即不能被识别。识别误差的分布情况和元音的音位很有关系,音位相近的元音较易互相误辨。文中比较了信号时程的长短在元音识别中及在声音音调辨别中的不同作用,并讨论了差异的原因。 When the syllable duration is longer than 60 milliseconds, the recognition rate of six unitary tones in Mandarin is always above 95%. When the syllable duration is shorter than 60 milliseconds, the vowel recognition rate gradually decreases with the shortening of the duration. When the syllable is as short as 8-13 ms, the vowel can not be recognized. The distribution of recognition errors is closely related to the phonemes of vowels, and vowels with similar phonemes are easier to misidentify each other. In this paper, we compare the different roles of signal durations in vowel recognition and sound pitch discrimination, and discuss the reasons for the differences.