Continuous versus categorical aspects of Japanese consecutive devoicing

Abstract

The phenomenon of high vowel devoicing is almost obligatory in the Tokyo dialect, except for some environments in which complete devoicing is often blocked. One such case is so called consecutive devoicing, where two or more consecutive vowels are in devoicing environments. Although several accounts of consecutive devoicing have been proposed, its linguistic nature is still being debated. The current study presents a detailed investigation of the nature of consecutive devoicing in Japanese, examining the influence of various factors on its likelihood, speaker variability, and phonetic realization. Twenty-four native speakers of Tokyo Japanese produced 30 words containing consecutive devoicing environments. Mixed-effects modeling revealed that several phonetically and phonologically motivated factors simultaneously contribute to the likelihood of consecutive devoicing and the pattern of partial devoicing. Wide intra- and inter-speaker variability was observed, indicating that realization of consecutive devoicing is not always consistent within a speaker, and that the relative weight of conditioning factors may vary across speakers. Vowel duration in consecutive devoicing environments (which reflects partial devoicing) showed a bimodal distribution, indicating that realization of consecutive devoicing cannot be determined solely by its phonetic environment. Taken together, the results demonstrate both continuous and categorical aspects of consecutive devoicing in Japanese.