External Vowel Sandhi in Castilian Spanish: An Acoustic Study of Vowel Sequences Across Word Junctures

In Spanish, words may begin or end with a vowel, creating a scenario where two vowels meet across a word juncture, such as in mono enano "dwarf monkey." Vowel sequences of this sort are said to be affected by a post-lexical process of hiatus resolution in which one of the two vowels becomes a glide. This study explores the acoustic-phonetic characteristics of vowel sequences across word junctures in Castilian Spanish. We focus on vowel sequences with no high vocoids: /ea ae eo oe/. Production data were collected from a sample of 23 speakers, and acoustic analyses focused on duration and the shape of first (F1) and second formant (F2) tracks. Our findings suggest that cross-lexical vowel sequences are resolved via a phonetic coalescence process that retains some of the linearity in (or recoverability of) the underlying sequence, displaying both some diphthongal qualities and some blending qualities. We find no obvious evidence of a "dominant" (syllabic) vowel in the sequence, casting doubt on impressionistic transcription-based descriptions postulating a strict dichotomy between syllabic vowels and glides in post-lexical syllable contraction. We discuss alternative accounts of the resolution of Castilian Spanish vowel sequences across word junctures couched within the framework of Articulatory Phonology, and we argue that post-lexical hiatus resolution is not a phonologized process in this language variety.