Vowel/glide alternation in a theory of constraint interaction
This dissertation examines the distribution of high vowels and glides using Prince and Smolensky's Optimality Theory, which proposes that phonological constraints are violable and hierarchically ranked. The distribution of high vowels and glides is shown to be a consequence of simultaneously comparing moraic and nonmoraic syllabifications of high vowels for satisfaction of phonological constraints. In brief, a high vowel surfaces when the moraic parse best satisfies the constraints and a glide surfaces when the nonmoraic parse best satisfies the constraints. This dissertation investigates three main phenomena associated with the distribution of high vowels and glides.
First, it treats the syllabification of vowel sequences in a number of languages with only surface monophthongal vowels. In Etsako, Luganda, Kimatuumbi, and Ilokano, high vocoids are syllabified as vowels when followed by a consonant, but they are syllabified as their nonmoraic counterparts when followed by another vowel. Furthermore, the syllabification of nonhigh vowels varies across these languages. The syllabification of vowel sequences is shown to follow from the interaction of syllable structure constraints that ensure the surface vowel is a monophthong. The interlinguistic variation in syllabification is shown to follow from different rankings of the same set of syllable structure constraints.
Second, stress can influence the distribution of high vowels. In Lenakel and Spanish, the generalization is that a high vocoid adjacent to a nonhigh vowel is a vowel when stressed otherwise it is a glide. This generalization implies that stress placement must be known prior to syllabification, which is problematic in procedural approaches to constituent construction, where syllabification must precede metrification. In the Optimality-Theoretic approach, the distribution of high vowels is determined by simultaneously best satisfying the metrical and the syllable structure constraints.
Third, the distribution of high vowels and glides cannot always be attributed to an alternation between underlying vowels and glides. In a language like Berber, glides must be present underlyingly, and these underlying glides can alternate with high vowels. This is often called glide vocalization. The alternation between underlying glides and high vowels in Berber is also shown to be the result of constraint interaction. In this case, moraic and nonmoraic syllabifications of the underlying glide are compared for constraint satisfaction.