粵東閩方言有項特殊的音韻現象,就是m、n、ng三組鼻音韻尾的合流。本文將以筆者所調查的粵東閩方言調查的成果,對m、n、ng這三個鼻音韻尾分合的地理分布,進行語言、地理、年齡關係的交互研究。經研究後發現,粵東閩方言的鼻音韻尾由內而外依次形成ng→m/ng→m/n/ng的分布,符合周圈論原則。並藉由グロットグラム(glottogram)的研究,發現單一ng韻尾與m、ng二組尾韻的形式仍在向外擴展。最後則對文獻上所見的此變化現象,與語言地圖上所見加以比較。我們認為此區鼻音韻尾合流成m、ng二組的時間,應該早在十六世紀就已出現,而非之前學者所認為的十九世紀。
The merger of the nasal codas -m, -n, and -ng is a special phonological phenomenon of the Min dialect of Eastern Guangdong. Through the linguistic map, it is noted that we can find that Type 1 (only -ng coda) is found in the center, Type 3 (-m, -n, -ng codas) are distributed on the periphery, and Type 2 (-m and -ng codas) are in between, which fits perfectly with the theory of concentricity. By using glottograms, I show that Type 1 and Type 2 are expanding outward and that the merging of nasal codas forming Type 2 happened in the 16th century instead of in the 19th century, as previously indicated in the literature.