HISPhonCog 2023: Hanyang International Symposium on Phonetics & Cognitive Sciences of Language 2023
May 26-27, 2023, Hanyang University, Seoul, Korea

Place Assimilation of the Moraic Nasal to /r/ in Japanese
Maho Morimoto1, 2, Ai Mizoguchi3, 4 & Takayuki Arai1
1

Sophia University (Japan), 2JSPS (Japan), 3Maebashi Institute of Technology (Japan), 4NINJAL (Japan)
maho.morimoto.jp@gmail.com, aimizoguchi@maebashi-it.ac.jp, arai@sophia.ac.jp

Background: The Japanese moraic nasal /N/ is known to regressively assimilate to the following
plosives in terms of place of articulation (e.g., [1, 2]), as is demonstrated by several articulatory
studies (e.g., [3, 4, 5]). /N/ is generally thought to assimilate not only to plosives but also to theliquid consonant /r/ (e.g., [1, 6]). However, the paucity of experimental data observing the actual
articulatory behavior limits our understanding of the gradient nature of the process.
We address two aspects of liquids for which the assimilation may not work as in the othercoronal consonants. First, the constriction location of Japanese /r/ is known to vary considerably[7], including those that are more posterior than in other coronals (e.g., [7, 8]). Second, in theframework of Articulatory Phonology (AP; [9]), the possibility that liquids are cross-linguisticallygesturally complex segments involving the coordination of coronal and dorsal gestures has been
explored [10]. Different views exist as to whether this applies to Japanese /r/ as well [8, 11]. In thisstudy, we report the results from an ultrasound study to examine the place assimilation of theJapanese moraic nasal /N/ to /r/ and the extent to which it differs from the assimilation to /d/ and/n/ as well as the utterance-final /N#/.
Methods: The current study reports data from two native speakers of Tokyo area Japanese (onefemale, AJF01, and one male, AJM01, both in their 20s). We report the articulatory results for theitems shown in Table 1. Each word was presented 10 times in a random order and the participants
read them aloud in isolation. Audio and ultrasound recordings were obtained simultaneously. For
the analysis, the midsagittal tongue contours at the acoustic midpoint of each target consonant weremanually traced using GetContours [12].
Results & Discussion: Fig. 1 shows the tongue contours for the target segments in each speaker,
predicted from the repetitions with 95% confidence intervals using the generalized additive model(GAM; [13]). Overall, the results confirm the traditional description in which coda nasals assimilate
in place to plosives and liquids. An additional finding is that the constrictions for /d/, /n/, and /r/
are more apical, as inferred from the concave shape at the tongue blade, while the constrictions for/N/ in /Nd/, /Nn/, and /Nr/ are more laminal, as indicated by the more convex shape. This may be
a result of a gestural planning specific to assimilated nasals through which speakers achieve aprolonged and more stable tongue tip (TT) constriction. Alternatively, this may be explained as
gestural blending in the framework of AP. Assuming that there is an underlying tongue body (TB)
gesture for /N/, as suggested in [4], the need to raise the TT and TB simultaneously may result inthe slight raising of the tongue blade. This is schematized in Figs. 2a and 2b, following the box
notation in [9].
The tongue contours for /r/ and /Nr/ suggest that the constriction location of the TT is higher
and more posterior than that of the obstruents, especially for AJF01. Furthermore, we observe aslight bulge around the TB area for /r/ and /Nr/ for both speakers. While this may simply be viewed
as a by-product of the retracted TT constriction, possibly involving a concentration of the mass dueto the contraction of the tongue surface muscles, it is also consistent with the view that the Japanese/r/ is gesturally complex. As shown in Fig. 2c, the bulge in the TB area may be accounted for as
the cumulative effect of the intrinsic dorsal gestures of /r/ and /N/.
Conclusion: The current study reported the differences among the tongue contours of /N/ followed
by /r/ and the other consonants, /d/ and /n/. Further investigation is needed to test the analyses
discussed above and obtain a full picture of the assimilation process. Our results also highlight theneed to combine point-tracking techniques such as EMA and whole-tongue imaging techniquessuch as ultrasound or rtMRI to better understand the nature of the lingual gesture involved in theproduction of /r/ (i.e., retraction as a horizontal displacement of the tongue body vs. sliding backof the tongue surface).

Table 1 Experimental stimuli (target segments are indicated in red).
/NC/
/C/
/Nd/
/aNda/
あんだ‘a hit’/d//hadaka//Nn//aNna/‘like that’/n//anata/
あんな/Nr//haNra/はんら‘half-naked’
/r/
/ara/
/N#/
/kaNaN/–
かんあん ‘consideration’ –はだかあなたあら–‘naked’‘you’‘coarseness’–

Figure 1 GAM contours with 95% confidence intervals for the seven target segments in each speaker.
The gray line above the tongue contours shows the palate contour.

Figure 2 Partial gestural scores showing the activation intervals of consonantal gestures.
References[1] Vance, T. J. (2008). The Sounds of Japanese. Cambridge University Press.
[2] Labrune, L. (2012). The Phonology of Japanese. Oxford University Press.
[3] Stephenson, L., & Harrington, J. (2002). Assimilation of place of articulation: Evidence from English
and Japanese. Proceedings of the 9th Australian International Conference on Speech Science andTechnology, 592–597.
[4] Mizoguchi, A. (2019). Articulation of the Japanese Moraic Nasal: Place of Articulation, Assimilation,and L2 Transfer. Ph.D. dissertation.
[5] Maekawa, K. (2021). Production of the utterance-final moraic nasal in Japanese: A real-time MRIstudy. Journal of the International Phonetic Association, 1–24.
[6] Akamatsu, T. (1997). Japanese Phonetics: Theory and Practice. (Vol. 3). Lincom Europa.
[7] Kawahara, S., & Matsui, F. M. (2017). Some aspects of Japanese consonant articulation: A preliminary
EPG study. ICU Working Papers in Linguistics, 2, 9–20.
[8] Morimoto, M. (2020). Geminated Liquids in Japanese: A Production Study. Ph.D. dissertation.
[9] Browman, C. P., & Goldstein, L. (1989). Articulatory gestures as phonological units. Phonology, 6(2),201–251.
[10] Proctor, M. (2011). Towards a gestural characterization of liquids: Evidence from Spanish and Russian.
Papers in Laboratory Phonology, 2(2), 451–485.
[11] Yamane, N., Howson, P., & Wei, P.-C. G. (2015). An ultrasound examination of taps in Japanese.
Proceedings of ICPhS XVIII, 1–4.
[12] Tiede, M. K. (2022). GetContours. GitHub repository, https://github.com/mktiede/GetContours.
[13] Wood, S. N. (2006). Generalized Additive Models: An Introduction with R. Chapman and Hall/CRC.