Boundary-driven downstep induced by syntax-prosody mapping.

This study investigates whether downstep in Japanese is directly triggered by accents. When the pitch height of a word X is lower after an accented word (A) than after an unaccented word (U), X is diagnosed as downstepped. However, this diagnosis involves two confounding factors: the already lowered F0 before X and phonological phrasing. To control these factors, this study contrasts genitive and nominative case markers and adjusts measurement points. Eight native speakers of Tokyo Japanese participated in a production experiment. The results show six key findings. First, a structure-dependent F0 downtrend was observed in UX. Second, higher F0 peaks with larger initial lowering were observed after accents with a nominative case marker compared to those with a genitive case marker, suggesting a boosting effect by boundaries. Third, larger initial lowering was observed in AX compared to UX, contradicting the notion that X is more compressed in AX due to downstep. Fourth, the paradigmatic difference in F0 height between AX and UX decreases when F0 of X is increased, supporting that boundaries trigger downstep. Fifth, downstep is not physiologically constrained but is phonologically controlled. Finally, the blocking of initial lowering in heavy syllables is not phonological but rather an articulatory phenomenon.