Boundary-driven Account for Downstep in Japanese
Kei Furukawa 1 and Satoshi Nakamura 1

1Nara Institute of Science and Technology, Japanfurukawa.kei.fi4@is.naist.jp, s-nakamura@is.naist.jp

Summary••••

Results

This study verifies the boundary-driven account for downstep in Japanese:
downstep is triggered not directly by accents but by phonological boundaries
Nine native speakers of Tokyo Japanese participated in a production
experiment
A new type of F0 downtrend: final-accented downstep.
• a stair-step-like F0 downtrend caused by final-accented words withoutparticles, with a smaller F0 fall than downstep.
Our finding indicates that accents do not directly trigger downstep•

the [+accent/-particle] condition did not show a large F0 downtrend• contrary to the prediction from the accent-driven accountthe small step-like downtrend found in the [+accent/particle] level isslightly larger than the downtrend in the [-accent/-particle] level•

Table 2: Results of mixed-effects models for R1Fall.

Table 3: Results of mixed-effects models for R1MaxF0.

Backgrounds••••In Tokyo Japanese, words are classified as either accented or unaccented• Unaccented (U)＝no sharp F0 fall
• Accented (A)＝H*L = F0 fallDownstep• Pitch range compression triggered by lexical pitch accent [1]• If the pitch height of X is AX < UX, then X is downstepped [2,3]• The assumption: downstep is triggered only by accented words
Boundary-driven downstep• The insertion of boundaries triggers a step-like F0 downtrend that
resembles downstep, even without accents [4]• A phonological boundary must be inserted after every accent owing toaccent culminativity and anti- lapse constraints [3]Research Question: Which account is more accurate: the accent-driven
account or the boundary-driven account?

Table 4: Results of mixed-effects models for R2MaxF0.
Figure 5: Sample F0 contours of all conditions.

Figure 6: Mean of normalized F0 means per
mora for item 1, item 2, and item 3. The [accent, -particle], [+accent, -particle], [accent, +particle], and [+accent, +particle]
conditions are represented by solid black,solid gray, dashed black, and dashed graylines, respectively.

Figure 1: Schematic of downstep

Discussions
Figure 2: Schematic of boundary-driven
downstep

Figure 3: Accent-driven vs. boundary-driven accounts

Our findings support the boundary-driven account rather than the accentdriven accountTwo facts indicate that there is no downstep in the [+accent, -particle]
condition:•1) the [+accent, -particle] condition did not exhibit a large F0compression for meeting the requirements for a paradigmatic
diagnosis•2) the [+accent, -particle] condition had a sufficiently higher F0 peakat Region 2 compared to the [+accent, +particle] condition
Are the phonological accents in the [+accent, -particle] condition deleted?
•No, because the Accent factor did create a slightly lower F0 peak atRegion 2 in the [+accent, -particle] condition than in the [-accent, particle] condition.

•••

Method••••Participants: A total of 9 native speakers of Tokyo JapaneseProcedure: Production experiment
Measurement:•
R1Fall: the maximum value of the pitch in N1 minus the minimum
value of the pitch of the following conjunction ya•
R1MaxF0: the normalized F0 maximum in Region 1.
•
R2MaxF0: the normalized F0 maximum in Region 2.
LME [5], backward selection [6]Figure 4: Schematic of final-accented words

Boundary-driven downstep•
a phonological mechanism that lowers the pitch of subsequent
PPhrases when a PPhrase or a PClause directly dominates two or
more PPhrases•(PPhrase1(PPhrase2X)(PPhrase3Y)(PPhrase4Z))
Accented downstep•a step-like large F0 downtrend after an accented word•
has traditionally been called downstep•one example of the phonetic realization of boundary-driven
downstep
Unaccented downstep•
a step-like small F0 downtrend after an unaccented word•
one example of the phonetic realization of boundary-driven
downstep•••

Conclusion
Our experiment results reveal a step-like F0 downtrend that is smaller
than downstep, despite the presence of final accentsThus, our study contends that accented downstep in Japanese is causedby boundaries rather than directly by accents••

Selected References
1. W. J. Poser, The phonetics and phonology of tone and intonation in Japanese (Doctoral dissertation), 1984.
2. H. Kubozono, The Organization of Japanese Prosody, 1988.
3. J. Ito and A. Mester, “Prosodic subcategories in Japanese,” Lingua, vol. 124, pp. 20–40, Jan. 2013.
4. K. Furukawa and Y. Hirose, “Boundary-driven downstep in Japanese,” Proceedings of 19th ICPhS, Canberra: ASSTA,2019.

5. D. Bates, M. Maechler, B. Bolker, S. Walker, R. H. B. Christensen, H. Singmann, B. Dai, G. Grothendieck, and P.

Green, “Package “lme4,” 2015.

Table 1: Sample stimuli used in experiment: Accented moras are underlined.

6. D. Bates, R. Kliegl, S. Vasishth, and H. Baayen, “Parsimonious mixed models,” Jun. 2015.