ON NEUTRAL-TONE SYLLABLES IN MANDARIN CHINESE

ON NEUTRAL-TONE SYLLABLES IN MANDARIN CHINESE

ON NEUTRAL-TONE SYLLABLES IN MANDARIN CHINESE

(汉语普通话轻声的声学特性)

摘要：本文通过对200多个轻声词的声学分析，考察普通话轻声音节的声学特性。实验分析结果说明，轻声音节之所以听起来轻，是因为它的能量较弱，这是音高、音长、音强和音色四要素总体弱化的综合效应，而不仅仅是音强变弱的单一结果。具体说来，轻声音节的音高模式中和化了，失去了它正常重读时的声调区别；音长缩短了，大约为正常重读音节的一半左右；音色相对弱化，例如清辅音往往会浊化，元音趋于央化，但原有音色仍可分辨；音强普遍偏低，但是，第三声音节之后的轻声音节，其音强不但不偏低，还反而普遍偏高。所以，音强不是构成轻声的主要特性，相对说来，音高和音长的变化是构成轻声的更为重要的特性。

I. INTRODUCTION

One of the characteristic and hard to be grasped features in Mandarin Chinese is the so-called neutral-tone ( hereafter NT) syllables, which is neutralized from corresponding normal stressed syllables. Perceptually, the NT syllable sounds quite

weak, and must be attached to other syllable as a dependent morpheme in polysyllabic words. However, it does not equal to the unstressed syllables in common, in stead, it forms an important morphophonemic contrast to the normal type one in bisyllabic words. Consequently, it might be of benefit to Chinese speech processing to clarify the phonetic nature of the NT syllables.

Many relevant approaches from different viewpoint(Dong,1956;Lin and Yan,1980; Lin,1982) have been contributed before, this study is concerned in their phonetic characteristics. The discussion is based on a relevant acoustic measurements and analysis (Cao,1986) referred to a corpus of materials including over 200 of NT syllables, all of them are occurred as second morpheme in different category of neutral type bisyllabic words.

The hypothesis is that the perceptual feature of the NT syllables may be caused by a combination of multiple acoustic effects, in stead of any single factor. Therefore, this kind of syllables must own their special acoustic patterns.

II. EXPERIMENTAL RESULTS AND DISCUSSION

2.1 The intensity of NT syllables

Perceptually, the stress of NT syllables is weaked, so people are often used to regard that it is a result of low intensity. However, the data obtained here illustrate that the intensity of NT syllable is not necessary lower than that of the syllable with normal stress. Table I offers a comparison on average intensity between normal syllables and the NT ones obtained from a set of duplicated bisyllabic words, in which two syllables with the same phonetic structure but different stress type. The corresponding figures show clearly that the intensity of NT syllable is lower than that of the normal one in general, but the situation is just reversed when it is

preceded by a third tone syllable. This tendency also can be seen from Fig 1, so it seems to be a relational invariance in this area. Therefore, the stress of NT syllable is weaked, but not simply related to its intensity.

Table I. Comparison on average intensity(dB) between normal

and NT syllables in duplicated neutral type bisyllabic