Prosodic Boundary Effect on VOT in Pharyngealised /tˁ/ and Plain /t/ in Libyan Arabic

Abstract

This study investigates the influence of prosodic boundary strength on voice onset time (VOT) in the pharyngealised-plain /tˁ, t/ contrast in Libyan Arabic. Acoustic data was designed with /V#tˁ/-/V#t/ sequences, yielding a hierarchy of prosodic boundary levels: Syllable, Word, Phrase and Intonation Phrase, and was obtained from six speakers of Libyan Arabic. Results show that voiceless plain /tʰ/ was aspirated, and produced with progressively lengthened VOTs across stronger prosodic boundaries. However, unaspirated pharyngealised /tˁ/ was produced with constant VOTs across all prosodic boundaries. These findings are discussed in contexts of prosodically driven phonetic implementation of individual segments, and provide evidence for paradigmatic contrast enhancement. Importantly, they suggest that low-level phonetic phenomena are not merely universal outcomes but are actively controlled by speakers in a language-specific way, requiring integration into the grammar of individual languages.