本文利用韻部例外演變的線索，說明方言同源詞無法利用《切韻》系統解釋的原因，並由此建立其語音規則對應，以進行論證，考求本字。
　　「例外演變」指的是與《切韻》系統不同的演變途徑。「例外」而可用來作論證的依據，乃由於其他同源詞也有相同的演變，它們共同形成為某種規則性變化，因此可以建立語音的規則對應，據以考證本字。
　　本文利用韻部例外演變的線索，說明閩南語 tshiu7 nã5（樹林）之 nã5 本字為「林」，pe7（父親）本字為「父」，tua7 ke1（夫之母）本字為「大姑」，mẽ5 kak4（事物的隱微關鍵之處）本字為「芒角」。這樣的研究，增加了我們過去所不知道的語音知識，是利用尋音法考求本字的一種嘗試。

　　This article tries to show the reason why regular reflexes, according to the Qieyun system, fail in identifying cognates in dialects and to suggest an alternative way by using exceptional developments of final categories, which may reveal some implicit regular correspondences. ‘Exceptional developments’ refers to developments differing from ones based on the Qieyun system. This is because of some parallel outcome shared by so-called exceptional cases that makes them regular in a different way and therefore could be used in identifying cognates. Examples from Southern Min dialects are given in this article. They are: nã5 ‘林’ in tshiu7 nã5 (樹林), pe7 ‘父’ in pe7 (父親), tua7 ke1 ‘大姑’ in tua7 ke1 (夫之母), and mẽ5 kak4 ‘芒角’ in mẽ5 kak4 (事物的隱微關鍵之處). It is hoped that a method like this could increase linguistic knowledge and help more in the study of cognates.

韻部例外演變; 語音規則對應; 同源詞研究; 閩南語

exceptional developments of final categories; regular sound correspondence; study of cognates; Southern Min