在衍生音韻學理論中，滑音常被視為元音因受制於音節或韻律規則所產生的變體，但本文提出新證據再次確立排灣語元音與滑音之間的音位對比。本文以音節劃分及重疊詞為新證據，重新分析過去文獻指出的現象，即重音分布與詞素音位交替，皆同時指出排灣語牡丹方言對於元音／滑音音位對比的需求。此研究除了提出一個全面的分析，釐清底層滑音和衍生滑音在表層形式所造成的混淆，更進一步討論元音和滑音於音節內部結構的歸屬，以及音段分布上的差異。此外，排灣語的底層滑音顯現輔音的特質，而衍生滑音則表現了元音的特性。

This paper shows that it is necessary to posit a phonemic distinction between the high vowels /i u/ and the glides /j w/ in Sinvaudjan Paiwan, although the latter are usually taken to be alternants of the former in phonological theory, conditioned by syllabic or metrical position. I provide evidence in support of this distinction and offer a unified account which is in accord with the established evidence from stress and morphophonemic alternations. The contrast between the vowels and glides is reflected in the segments’ moraic status and the internal structure of syllables, including the syllabic affiliation and distribution of phonemic vowels and glides. The confusion made by surface glides is also explained: phonemic glides, which are true consonants, pattern with consonants, whereas derived glides, which come from vowels, are mostly vowel-like.