Categorical and gradient effects in segmental deletion: The case study of /w/-deletion in Seoul Korean

Categorical and gradient effects in segmental deletion: The case study of /w/-deletion in Seoul Korean

An increasing body of evidence suggests that phonological processes exhibit both categorical and gradient effects. This study investigates categorical and gradient effects observed in /w/-deletion in Seoul Korean and how the patterns differ by context. Using ultrasound and a side-view camera, midsagittal images of the tongue and lip protrusion of four participants were recorded. The speakers participated in the task of explaining the semantic differences between 18 words of CV and CwV sequence (e.g. tweji ‘pig’ vs. teji ‘earth’). Optical Flow Analysis was used to quantify the magnitude of lip and tongue movement. Results show that different patterns of categorical and gradient effects of /w/-deletion are observed by context. When /w/ is preceded by a bilabial, /w/ tends to delete categorically, while both categorical deletion and gradient reduction appear to occur when /w/ is preceded by an alveolar or a velar. I argue that the categorical and gradient effects of a related phonological process can be present simultaneously, which can be accounted for by diachronic development of sound patterns.