Contrast Maximization in F0 Declination: Japanese Shiki-accent Dialects

Japanese dialects spoken in the Kinki and Shikoku regions have a lexical contrast of pitch register types called shiki. The shallow f0 downtrend in the high-pitched shiki type is thought of as a manifestation of backdrop f0 declination that is blind to tonal structure. Acoustic analysis of three Japanese dialects with 2or 3-way contrast of shiki types, however, reveals that the degree of f0 declination takes different values depending on the number and structure of contrastive shiki types. This can be regarded as dialect-specific ways of maximizing difference in f0 trends in word-sized units for enhancing contrasts between phonological categories, suggesting that f0 declination patterns in shiki dialects are encoded in the contrastive structure of their phonology.