Speech Rhythm Perception in Japanese: Evidence From Sensorimotor Synchronisation With Connected Speech.

The rhythm of Japanese has often been described as mora-timed, a characterisation that overlooks the richer prosodic hierarchy extending from the mora to the syllable, metrical foot and prosodic word. The present study examines rhythm perception in Japanese using a recently developed sensorimotor synchronisation technique. Forty native speakers of Tokyo Japanese participated in the experiment, synchronising in time with the beat of looped sentences spoken in their native variety. Analysing frequency, accuracy and stability of synchronisation, the study showed that the mora affected the perception of speech rhythm only indirectly, by shaping the structure of bimoraic metrical feet. The results suggest two core rhythmic domains in Japanese - the metrical foot and the prosodic word - whose initial elements attract rhythmic attention. This indicates a perceptual preference for a trochaic rhythm. The presence of a pitch accent enhanced synchronisation patterns observed within the domain of metrical feet, which signifies accentual rather than purely tonal perception of pitch accent. Given that the existence of a bimoraic foot unit in Japanese has been proposed based on a range of morphophonological phenomena, the present study is among the first to provide empirical evidence in support of the psychological reality of bimoraic metrical feet for Japanese listeners. We discuss these findings as evidence of a system of rhythmic constraints that is primarily edge-sensitive, with head-sensitivity playing a secondary role.