Boundary-driven downstep induced by syntax-prosody mapping

Area of Science:

• Phonetics and Phonology
• Linguistics
• Sociolinguistics

Background:

• Downstep in Japanese intonation is often diagnosed based on pitch height differences after accented (A) versus unaccented (U) words.
• Previous diagnoses are confounded by pre-existing pitch lowering (F0 downtrend) and phonological phrasing.
• Controlling for these factors is crucial for understanding the true triggers of downstep.

Purpose of the Study:

• To investigate whether Japanese downstep is directly triggered by accents or other linguistic factors.
• To differentiate between accent-driven downstep and boundary-induced pitch lowering.
• To clarify the phonological versus physiological constraints on pitch variations in Japanese.

Main Methods:

• Production experiment with eight native Tokyo Japanese speakers.
• Controlled for confounding factors by contrasting genitive and nominative case markers and adjusting measurement points.
• Analyzed fundamental frequency (F0) contours in accented (AX) and unaccented (UX) contexts.

Main Results:

• Observed a structure-dependent F0 downtrend in UX contexts.
• Nominative case markers showed higher F0 peaks and greater initial lowering after accents, suggesting a boundary-boosting effect.
• Larger initial lowering in AX compared to UX contradicted the idea of pitch compression due to downstep; downstep appears triggered by boundaries.

Conclusions:

• Japanese downstep is phonologically controlled and triggered by phrase boundaries, not directly by accents.
• The observed pitch lowering is not physiologically constrained but phonologically determined.
• Blocking of initial lowering in heavy syllables is an articulatory, not phonological, phenomenon.