從《切韻》序、《經典釋文》序錄和《顏氏家訓‧音辭篇》的記載可知，上古漢語到了六朝時期，至少已經分裂為南北兩個主要的方言群，一是北方的河北方言（鄴下音系），一是南方的江東方言（金陵音系）。（丁邦新 2008[=1995]）根據梅祖麟（2001、2013）的假設，現代南方方言中的閩語、吳語及北部贛語都存在一個江東方言的層次。在這個前提之下，本文準備利用閩語的豐富材料，透過同源詞比較及層次分析，配合漢語音韻史及漢語詞彙史的研究成果，構擬江東方言蟹攝二等開口皆佳夬諸韻的音值。整體而言，本文研究的課題如下：
1. 利用中古切韻提供的韻攝框架，觀察閩語各次方言中蟹攝二等開口字的現象，進而分析出不同的語言層次。
2. 根據漢語音韻史及漢語詞彙史的知識，判斷不同語言層之間彼此在時間上的先後關係。
3. 利用相應的音韻層次來構擬六朝時期古江東方言蟹攝二等開口字的音韻形式。
　　本文的研究指出，原始閩語中的蟹攝開口二等皆佳夬韻具備條件分化，依據聲母條件不同，可以分別構擬為 *-ɨəi 皆佳夬韻幫見影系 /*-ei 皆韻莊系 /*-ɛi 佳夬韻莊系。從漢語詞彙史及漢語音韻史的表現來看，南朝江東方言的蟹攝二等開口字也可以構擬為相同的形式。

　　According to the Chinese written documents (e.g. Qie Yun Introduction, Jing Dian Shi Wen Introduction and The Yin Ci Chapter of The Family Instructions of Master Yan ), it is clear that there are two main dialects in Northern and Southern Dynasties: one is Ye Xia dialect and the other is Jin Ling dialect. (Ting 2008[=1995]) Furthermore, Mei (2001 & 2013) proposed a hypothesis that the Min dialect, Wu dialect and northern Gan dialect share a common stratum descended from Southern Dynasty Jiang Dong Dialect. Based on this premise, this paper will reconstruct the phonological forms of the unrounded grade-2 finals, i.e. Jie, Jia and Guài rhymes, of Xiè rhyme group through comparison of modern Min dialects. Generally speaking, the aims of this article are:
1. to investigate the cognates of unrounded grade-2 finals of Xiè rhyme group in Min dialects and to analyze the different strata with the Qie-yùn framework.
2. to clarify the sequence of different strata with Chinese historical phonology and Chinese lexical history.
3. to reconstruct the values of unrounded grade-2 finals of Xiè rhyme group with correct phonological stratum in Min dialect.
　　This paper concludes that the phonological forms of unrounded grade-2 finals of Xiè rhyme group in proto Min are *-ɨəi, *-ɛi and *-ei in different consonant environments: *-ɨəi is after bilabials, velars and glottals, whereas *-ɛi and *-ei are both after postalveolars. From the perspective of Chinese historical phonology, the medial *-ɨ- of final *-ɨəi in proto Min can be traced back to medial *-r- in old Chinese.

閩語; 蟹攝二等開口字; 古江東方言; r 介音; 比較方法; 歷史語言學

proto Min; unrounded grade-2 finals of Xiè rhyme group; Jiang Dong dialect; medial *-r-; comparative method; historical linguistics