There is growing evidence that speech sound acquisition is a gradual process, with instrumental measures frequently revealing covert contrast in errors perceived to involve phonemic substitution. Ultrasound imaging has the potential to expand our understanding of covert contrast by showing whether a child uses different tongue shapes while producing sounds that are perceived as neutralized. This study used an ultrasound measure (Dorsum Excursion Index) and acoustic measures (VOT and spectral moments of the burst) to investigate overt and covert contrast between velar and alveolar stops in child speech. Participants were two children who produced a perceptually overt velar-alveolar contrast and two children who neutralized the contrast via velar fronting. Both acoustic and ultrasound measures revealed significant differences between perceptually distinct velar and alveolar targets. One child with velar fronting demonstrated covert contrast in one acoustic and one ultrasound measure; the other showed no evidence of contrast. Clinical implications are discussed.
The syllable-final Japanese moraic nasal /N/ is commonly transcribed as velar or uvular or even placeless, but very little articulatory has been reported. This study investigated the tongue shape and position for /N/ in various phonological environments using ultrasound. /N/ assimilates to the place of following segments, so a variety of environments was also examined to assess whether the assimilation occurs categorically or gradually. Tens repetitions of 7 target words with a moraic nasal (/aNCa/, /aNa/, /aNaN/, and /ƜN/) and 6 control words without a moraic nasal (/aCa/, /aa/) were spoken by 4 native speakers of Japanese. Although there seems to be an oral target for moraic nasal, the place was different for each of our four speakers. The assimilation also varied among speakers, but a gesture for the moraic nasal remained in at least one phonological environment for all the speakers. Assimilation of Japanese moraic nasal to following segments is not always categorical and a gesture for the target of moraic nasal, even though varying among individuals, remains depending on the phonological environments. The ambiguities in transcribing /N/ seem to be reflecting the state of the language accurately: Even with four speakers, four patterns emerged. [Work supported by NIH DC-002717.]
The Japanese mora nasal /ɴ/, which occurs in syllable-final position, takes its place of articulation from the following segment if there is one. However, the mora nasal in utterance-final position is often transcribed as velar, uvular, or even placeless. The present study examines the tongue shapes in Japanese using ultrasound imaging to investigate whether Japanese mora nasal /ɴ/ is placeless and to assess whether assimilation to following segments is gradient or categorical. Preliminary results from ultrasound imaging from one native speaker of Tokyo dialect showed three shapes for final /ɴ/, even though the researchers could not distinguish them perceptually. Results from assimilation contexts showed that the velar gesture for /ɴ/ was not deleted. All gestures remained and assimilation was not categorical, even though perceptually, it was. The velar gesture for /ɴ/ might be expected to be deleted before an alveolar /n/ because they are both lingual, but a blending of the two tongue gestures occurred instead. Variability in place of articulation in final position occurred even within one speaker. Categorical assimilation was not observed in any phonological environments studied. The mora nasal may vary across speakers, so further research is needed to determine whether it behaves similarly for more speakers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.