Raphael L J, Dorman M F, Freeman F, Tobin C
J Speech Hear Res. 1975 Sep;18(3):389-400. doi: 10.1044/jshr.1803.389.
To determine durational differences between vowel and nasal segments preceding word-final /t/ and /d/, spectrograms were made of adult speakers' productions of minimal pairs of the type /pent/-/pend/. Vowel, nasal, and vowel plus nasal (vocalic nucleus) durations were greater before /d/ than before /t/. Assuming the voiceless context as a base, the increase in nasal duration in the voiced case was proportionately greater than the increase in vowel duration. This outcome suggests that nasal duration is a more powerful cue to the voicing characteristic of the following consonant than is vowel duration. To test this, adult listeners were presented synthetic CVNC utterances in which the nasal and vowel segments were independently varied in duration over a range of 40 msec to 200 msec and were instructed to label the final stop consonant as either voiced /d/ or voiceless /t/. Although changes in both vowel and nasal duration were sufficient to cue both voiced and voiceless judgements, listeners' categorization of final consonants shifted more rapidly as a result of varying nasal rather than vowel duration. Nasal duration, therefore, appears to be a stronger cue than vowel duration for the word-final voiced-voiceless consonant distinction in CVNC utterances.
为了确定词尾/t/和/d/之前的元音和鼻音段的时长差异，对成年说话者发出的/pent/-/pend/这类最小对立体的语音制作了频谱图。/d/之前的元音、鼻音以及元音加鼻音（元音核心）的时长比/t/之前的更长。假设以清辅音语境为基准，浊辅音情况下鼻音时长的增加幅度相对大于元音时长的增加幅度。这一结果表明，对于后续辅音的浊音特征而言，鼻音时长是比元音时长更强有力的线索。为了验证这一点，向成年听众呈现了合成的CVNC语音，其中鼻音和元音段的时长在40毫秒至200毫秒的范围内独立变化，并要求他们将词尾塞音标记为浊音/d/或清音/t/。尽管元音和鼻音时长的变化都足以提示浊音和清音的判断，但由于鼻音时长而非元音时长的变化，听众对词尾辅音的分类转变更为迅速。因此，对于CVNC语音中的词尾浊音-清音辅音区分，鼻音时长似乎是比元音时长更强的线索。
