Articulatory evidence of consonant cluster simplification in L1 Korean: An ultrasound study

While Korean orthography allows stem-final consonant clusters, phonologically only a single consonant may occupy the coda position. As a result, consonant cluster simplification (CCS) is typically obligatory in spoken Korean. However, recent studies Kang et al., 2004; Yun, 2023 have reported variation in production, including cases where both consonants appear to be retained. Most prior work has relied on perceptual or acoustic data, which provide limited insight into articulatory mechanisms. This study investigates whether CCS involves complete articulatory deletion or whether traces of the “deleted” consonant persist in tongue movement. Using ultrasound imaging, this study analyzed the /lk/ cluster by comparing malkta ‘clear’ (맑다) with control items makta (막다) and maltta (말따). Three native Korean speakers produced tokens in both isolated and sentential contexts. Tongue movement data were collected using the Articulate Assistant Advanced system and qualitatively analyzed. Results reveal gestural overlap, with tongue tip elevation for /l/ and dorsum raising for /k/ occurring sequentially or simultaneously in many tokens. These findings suggest that articulatory traces of both segments may persist even when one is not acoustically or perceptually realized, providing evidence for covert articulation in Korean CCS.