前人的研究顯示布農語的滑音不是獨立的音位，在表層的滑音其實是由底層元音變化而來的，目的是為了避免零聲母的音節。採用此聲母原則意含了在表層不應有元音串出現，相鄰元音之其一應會變成滑音以滿足音節必須有聲母的要求。本文探討南投縣仁愛鄉卓社布農語的滑音形成是否單純受聲母原則支配。所蒐集的語料顯示，當詞素加綴而產生元音串時，底層元音不一定會依聲母原則的預測轉換為滑音。本文認為其中一個滑音形成規律的例外情形是為了滿足實詞必須至少是一個雙音節的韻律詞的要求。另一個滑音形成規律的例外情形發生在元音結尾的詞幹後接元音起始的後綴時；本文認為滑音形成規律不發生的原因，和未加後綴型式詞幹的末音節重音有關，意即詞幹未加後綴時末音節帶重音的元音在加綴型式中傾向不變成滑音。最後本文以制約為主的優選理論架構，來捕捉滑音形成規律在卓社布農語中與聲母制約、重音、及實詞最小音長互動的關係。優選理論中的制約排序機制，比起傳統衍生音韻學中的規則排序，更適於描述此種規律中的例外乃導因於其他規律的情形。

Previous studies on Bunun have shown that glides in Bunun are not phonemic; they are derives from underlying vowels in order to said syllables without onsets. Adopting the onset principle implies that vowel sequence will not appear on the surface representation of Bunun. This paper examines whether glide formation in Takituduh Bunun is solely governed by the onset principle. The collected data show that there are two types of exceptions to the prediction that one of adjacent underlying vowels will turn into a glide. One type of exception occurs in order to satisfy the requirement that a content word must be a disyllabic prosodic word, the other involves the situation in which a vowel-ending stem takes a vowel-initial suffix. The paper proposes that the second type of exception is related to the final stress pattern in the language: the stressed vowels in the final syllables of non-suffixed forms tend to remain syllabic in corresponding suffixed forms. Finally, the paper formalizes the interactions among onset requirement, stress, and word minimality within the framework of Optimality Theory, and shows that constraint interactions better express the nature of such apparent exceptions to a phonological generalization than the traditional rules do.