Generational dynamics in velar palatalization: An acoustic study of Tohoku Japanese

This study examines the contextual and generational differences in consonantal palatalization of Tohoku Japanese compared to Tokyo Japanese. Typically, both Japanese dialects transform alveolar obstruents to alveo-palatals before /i/. Moreover, previous research has shown that Tohoku Japanese also exhibits palatalization of velar stops /k, ɡ/. However, this palatalization ceases to appear among the younger generations despite the scant acoustic evidence. This study aims to: (i) describe the occurrence of velar palatalization in Tohoku Japanese and (ii) analyze variations between Tohoku and Tokyo Japanese by socio-demographic factors including age and gender. Twenty-five speakers from Tohoku and twenty-one from Tokyo participated in a production task using target words containing /k/ in the /ki/ and /ka/ contexts, and /ʨ/ as the palatalization baseline. The results of Center of Gravity (CoG) revealed significant interactions between the target consonant, dialectal group, and age group in the palatalization patterns. Younger speakers of Tohoku Japanese show a similar CoG distribution that resembles those of Tokyo speakers, particularly in the pairwise comparison of /k/ in /ki/ and /ka/. This empirically suggests a converging shift among young Tohoku speakers toward the standard variation of Japanese, supporting a diminishing regional variation correlated with consonantal context and influenced by generational change.