普通話上聲變調形式的逆向協同發音作用

學界普遍認為連讀變調是音系層面的，協同發音是語音層面的，當一個聲調發生連讀變調之後，它對鄰近聲調的協同發音作用是以本調還是變調形式進行的，學界尚未展開充分的研究。本文以漢語普通話的上聲變調爲樣本考察這一問題，上聲的底層形式是低調，在另一個上聲前變為與陽平類似的升調。通過聲學實驗觀察上聲的不同表層語音形式對前接聲調的協同發音作用。結果顯示，陽平和半上聲對前一個聲調的逆向作用有顯著差異，而陽平和類似於陽平的變調上聲對前一個聲調的逆向作用則無差異。這些結果表明，上聲對前接聲調的逆向協同發音是以其表層的語音表達形式而不是底層音系形式為基礎的。這個結果同時意味著，發音人對連上變調規則的心理加工在發音之前已經完成，這與前人通過腦電研究上聲變調加工所得到的相關結果形成呼應。

It is widely acknowledged that tone sandhi is phonological, whereas tonal coarticulation is phonetic. However, when a tone undergoes tone sandhi, the question as to whether its tonal effect on adjacent tones is based on its underlying phonological form or its surface phonetic form has not been fully studied. Thus, this study chose Mandarin Tone3 sandhi (a tonal change in which a Tone3 [T3], which has an underlying low form, followed by another T3, is pronounced as a rising tone that resembles Tone2 [T2]) as a research sample to investigate the above-mentioned problem. An acoustic experiment was conducted to observe the tonal coarticulation effects of different tonal forms of T3 on their preceding tones. The results showed that there was a significant difference between the regressive effects of T2 and the low form of T3 on the preceding tone, whereas there was no significant difference between the regressive effects of T2 and sandhi T3 on the preceding tone. These results demonstrate that the regressive effect of T3 on the preceding tone is based on the surface phonetic form, rather than the underlying phonological form. Moreover, the results of this study suggest that psychological processing of the T3 sandhi rule has been implemented before pronunciation of the first T3 in the T3T3 combination, which is in accord with the related results obtained from a previous ERP (event-related potential) study on T3 sandhi processing.