“古四声不同今韵”与上古汉语韵尾构拟问题

除调型丶调值外,上古与中古汉语声调的差异体现在两个方面:一是调类,比如上古汉语的声调就有三调丶五调之说;一是每个字的具体归类,比如有些字中古是去声,上古属于平声。这两类差异,段玉裁称之为"古四声不同今韵"。各家构拟在反映古今调类总体差异方面,均言之成理。在古今异调字问题上,高本汉等学者的构拟体系缺乏解释力,但可以容纳对异调字的不同处理;而持声调源于韵尾假说诸家的构拟,则陷入逻辑困境,如何解释异调字从上古到中古的演变过程,是该假说面对的一个难题。

Besides the actual contour of tones, the differences between Old and Middle Chinese tones lie mainly in two aspects: the overall tone category and tone of individual characters. As to the former, there are studies claiming three or five tones in Old Chinese; as to the latter, it is a consensus that a few characters belong to different tones in Old and Middle Chinese. In this paper, we argue that all the previous reconstructions of Old Chinese codas can explain the difference in tone category between Old and Middle Chinese quite reasonably, but in accounting for the characters which developed into different tones from Old Chinese, the hypothesis that Chinese tones originated from post-codas is in an untenable situation.