The articulation of lexical and post-lexical palatalization in Korean

Palatalization in Korean is of two types lexical palatalization governed by language-specific phonological rules, and postlexical palatalization that appears to be purely phonetic. While lexical palatalization only occurs when a morpheme boundary intervenes between a target consonant and a palatalization trigger, post-lexical palatalization occurs irrespective of the presence of a morpheme boundary. This study investigates whether these two types of palatalization and different morphological structures of words manifest as distinct tongue gestures using ultrasound imaging of 4 native speakers of Korean. Comparison of the ultrasound tongue contours shows that the gestural distinction between lexical and post-lexical palatalization may not be the same across individual speakers. Furthermore, the effects of morpheme boundaries are not uniform across different coronal consonants and speakers in terms of tongue gestures. The findings from this study provide further empirical evidence for the role of morphological structures in coarticulation, and are in line with mounting evidence for speaker-specific variability in speech production.