Articulatory timing and sound change: a sociophonetic study of /st/ clusters in Seville Spanish

This dissertation investigates the phonetic realization of the consonant cluster /st/ in Sevillian Spanish, examining how social and temporal factors influence the articulation of /s/ before /t/. Four variants are analyzed: sibilant /s/, preaspiration [ʰt], postaspiration [tʰ], and resyllabification [tˢ]; which represents different stages in the weakening and restructuring of coda /s/. The study explores how these variants pattern across age, gender, prosodic, and morphological dimensions to better understand sound change and the role of articulatory timing in sibilant evolution. Data were collected from eighteen native Sevillian speakers through semi-structured interviews and a Controlled Reading Task (CRT). The interviews provided spontaneous speech data, while the CRT tested how increasing time pressure affects articulatory coordination and gestural overlap. Acoustic and auditory analyses followed established sociophonetic protocols, and results were evaluated using chi-square tests, and mixed-effects logistic regression. Findings show that while the canonical sibilant remains dominant, younger and females speakers increasingly favor postaspiration and resyllabification, consistent with Labovian models of sound change led by innovative groups. Preaspiration appears conservative, occurring in slower, stressed and nonmorphemic contexts. The CRT confirmed that shorter time intervals promote gestural overlap, reinforcing a model of change grounded in articulatory phonology. Together, these results demonstrate how social differentiation and temporal constraints interact to drive cluster restructuring and ongoing sound change in Sevillian Spanish.