A cineradiographic investigation of children's w/r substitutions.

Articulatory positioning and movement characteristics were compared between /w/ and intended /r/ productions in three children exhibiting w/r substitutions and one normal control subject. High-speed lateral-view cineradiography was utilized. It was found that only the control subject demonstrated significant differences in lip, jaw, and tongue positioning for /w/ compared to /r/. However, systematic patterns of articulatory variability within and between subjects suggested that the experimental subjects were possibly differentiating between /w/ and intended /r/ even though the articulatory target configuration appeared to be nondiscriminatory. Perceptual judgmnets of the tape-recorded utterances mirrored the physiological data in that only those intended /r/ productions involving articulatory positioning clearly different from that of /w/ were perceived as /r/.