宋代陸游《老學庵筆記》中就已論及：「四方之音有訛者，則一韻盡訛」，亦即現有漢語方言字音讀法與中古切韻音系的聲紐和韻類當有整齊的對應性，若屬於該韻類的一個字如此，那麼該韻母的其他轄字也應都如此讀。陳忠敏（2013）延伸此種觀點指出：文白讀層以音類為對立，是成系統的音韻對應；具系統性的文白讀音才是層次分析的依據。按照 Dixon（1997）的語言發展模式，一個處在原平衡期（equilibrium）的語言，語音會與其祖語系統對應，如同台灣四縣、海陸客家話和切韻音系相對的整齊關係。然而，語言可能因為劇烈接觸而產生疾變（punctuation），之後雖然逐漸穩定下來，達到新的平衡期，語言使用者對於每個字音的讀法產生共識，但語音系統已經「回不去了」，顯現多種來源的語言質素，跟祖語無法系統對應。
　　本文以台灣大埔音客語詞典（2005）內的單字讀音為基準，從對比分析的觀點，探討東勢客家語這個處於新平衡期階段的語言，系統對應上的不整齊性。以中古音架構出發，蒐羅範圍包含聲母的從母、溪母、曉影組，到韻母的果攝三等、蟹開一精、蟹開二幫、見、影組，效開三四、流開一三、梗開二四等之轄字，將東勢、四縣、海陸、饒平、大埔縣高陂鎮的語料進行比較，逐一辨認東勢客家語的不同質素，用實際證據說明其混合方言的性質。
　　我們將在本文中看到，四縣、海陸話較為接近李如龍在〈論語言的社會類型學研究〉（2009：376-9）中所說的封閉型語言，處於原平衡期，與祖語系統性地對應。而東勢客家語，歷史上因四縣、海陸、饒平、大埔話劇烈接觸，發生疾變之後，達到新的平衡期，音讀固定下來了，卻干擾了跟祖語對應的整齊性。以其廣納多種來源，本文主張可歸為李文所言之開放型語言。

　　Chen (2013) proposed that only systematic phonological correspondence can be the ground for historical strata analysis, which was discovered by Lu-you in Sung Dynasty. According to the language developmental model of Dixon (1997), languages in the original equilibrium period are stable; the correspondences between contemporary and ancient forms are regular, such as the relationship of Hakka Si-Xian accent and Qie-yun systems. Meanwhile, punctuation may occur due to language contact within a short time; a new equilibrium stage is achieved thereafter, but elements from various sources fell to be predictable as compared to their ancestral tongue.
　　We take a Hakka accent spoken in Dung-shih District, Taichung City as the instance of punctuation through Contrast Analysis. From initials to rhyme-groups, comparison is made among different sub-dialects of Hakka in both Taiwan and Canton. The hybridity of Dung-shih is then proved by checking the pronunciation recorded on the dictionary edited by Hsu (2005).
　　As we shall see in the article, Si-Xian accent is similar to the conservative type of language attributed by Li (2009), staying in the original equilibrium period. However, Dung-shih has gone through intensive language contact, which leads to punctuation. Owing to the multi origins, Dung-shih fits Li’s definition of the open type of language.

東勢客家語; 聲韻學; 開放型語言; 台灣大埔音客語詞典; 對比分析

Dung-shih Hakka; Chinese Phonology; the open type of language; Da-pu Hakka dictionary; Contrast Analysis