越南艾話是客家話一種。本論文集中討論越南北部艾話〔ts^h ~ s〕共時變異所反映的〔ts^h > s〕歷時音變。北部艾話在〔ts^h > s〕音變過程當中,有多位同個發音人在同個語詞上產生發〔ts^h〕、〔s〕或〔s^h〕的語音兩讀現象。這種現象不僅反映越南境內艾話〔ts^h > s〕的世代音變,同時也反映艾話音變過程的異質性。這種「語音漸變」特點,與詞彙擴散的詞彙漸變,以及語法化的新舊形式共存現象,分別在語音、詞彙和語法等不同層面上,反映出語言變化具有「異質並存」共性。此外,音變產生是由於越南艾人受到週遭其他族群的語言接觸影響,反映中國大陸西南部和越南北部一帶地理類型的語音特點。
This paper deals with [ts^h ~ s] variation in the Ngai language which is one sub-dialect of Hakka in Vietnam. The synchronic variation of [ts^h ~ s] in the Ngai language reflects the diachronic sound change of [ts^h > s]. During the process of sound change of [ts^h > s] in the Ngai language, many Ngai speakers pronounce the alternations between [ts^h], [s], and [s^h] on the same words. This phenomenon of alternations reflects both the generational sound change of [ts^h > s] in the Ngai language and its heterogeneity synchronically. The 'heterogeneous coexistence' of sound changes parallels the 'heterogeneous coexistence' of lexical diffusion and grammaticalization. In addition, this sound change is due to the language contact of the Ngai language with other ethnic languages. Northern Vietnam and southwestern China are the essential areas where language contact occurs with geographical characteristics.