An ultrasound examination of taps in Japanese

This paper used ultrasound technology to examine the plain and palatalized taps in Japanese. Six participants of Japanese produced nonsense words containing /ɾ/ and /ɾ/. The mid-sagittal contours were compared in three intervocalic contexts: a_a, o_o, u_u. The results showed that /ɾ/ had a great deal of variability around the tongue dorsum. This suggests that /ɾ/ lacks a dorsal gesture; unlike the other members of the rhotic class, it is solely a tongue tip gesture. /ɾ/ was articulated with a raised tongue body and fronted tongue dorsum. The palatalization gesture was resistant to coarticulatory effects, suggesting that it is important for contrast maintenance. The results also suggest that an inconsistency between palatalization and rhotics cannot be related to the constraints on the dorsal gesture because the dorsal gesture seems to be inert for the taps. Rather palatalization is likely to interfere with the apical gesture associated with rhotics.