運用方言比較、層次分析和類型學的方法，結合漢語語音史，本文全面 討論了《切韻》以後蟹止攝合口字與虞韻同韻，即所謂「支微入虞」的現 象。具體論題涉及：(1) 支微入虞廣泛分布於吳、徽、通泰、贛、客、老 湘、閩北、晉等大方言，其他官話、新湘、閩中、閩東等方言也有零星的表 現。(2) 該音變在轄字韻類按「止合三（支脂微）→蟹合三四（祭廢齊）→ 蟹合一（灰泰）」的相對次序推進；聲母類型上按「喉、舌尖前/舌面/翹 舌/舌葉→舌尖中→舌根→唇」的調音部位漸次推進。(3) 除了個別贛、閩北 方言，該音變在各方言中都是由內部結構性變化造成的白讀音。(4) 該音變 的性質及過程因韻類而異：止合三、蟹合三四為 *iuei > iui > iu > y（丟失韻 尾），蟹合一為 *uei > yei > yi > y（韻尾對介音的「隔音同化」），後者只 在 [y] 階段併入虞韻，前者可在 [iu]、[y] 兩個階段入虞，這也是蟹合一最後 入虞的原因之一。(5) 該音變在某種程度上可作為觀察方言關係的「晚期性 條件」，但入虞的不同韻類在判定上有不同的效果。

The phenomenon ‘Zhi (支) and Wei (微) convergence into Yu (虞)’ is a wellexplored topic in the field of Chinese dialectology and Chinese historical phonology. Through a comparison between modern dialects and an analysis of strata of dialects based on the material of Chinese historical phonology, this paper deals with the synchronic distribution and diachronic implication of this kind of sound change. This paper discusses:

1. The detailed reflexes of ‘Zhi (支) and Wei (微) convergence into Yu (虞)’ among Wu, Hui, Tongtai, Old Xiang, Gan, Hakka, Northern Min, Jin, other southwestern and northern Mandarin dialects, New Xiang dialects, Central Min and Eastern Min.

2. The relative sequence of rhyme categories and the type of initial consonants involved into the sound change.

3. The nature of the sound change in light of the literary and colloquial strata discrepancy and the different phonetic value produced when the related different rhyme categories belonging to Xie (蟹) and Zhi (止) groups converged into Yu (虞).

4. The earlier relationship between modern dialects from the perspective of this kind of sound change.

支微入虞; 共時類型; 歷時蘊涵; 音變性質; 現代方言; 漢語語音史

Zhi (支) and Wei (微) convergence into Yu (虞); synchronic distribution; diachronic implication; nature of the sound change; modern dialects; Chinese historical phonology