Prosody and melody in vowel disorder

The paper explores the syllabic and segmental dimensions of phonological vowel disorder. The independence of the two dimensions is illustrated by the case study of an English-speaking child presenting with an impairment which can be shown to have a specifically syllabic basis. His production of adult long vowels displays three main patterns of deviance - shortening, bisyllabification and the hardening of a target off-glide to a stop. Viewed phonemically, these patterns appear as unconnected substitutions and distortions. Viewed syllabically, however, they can be traced to a single underlying deficit, namely a failure to secure the complex nuclear structure necessary for the coding of vowel length contrasts

Feedforward and feedback control in apraxia of speech: effects of noise masking on vowel production

PURPOSE: This study was designed to test two hypotheses about apraxia of speech (AOS) derived from the Directions Into Velocities of Articulators (DIVA) model (Guenther et al., 2006): the feedforward system deficit hypothesis and the feedback system deficit hypothesis. METHOD: The authors used noise masking to minimize auditory feedback during speech. Six speakers with AOS and aphasia, 4 with aphasia without AOS, and 2 groups of speakers without impairment (younger and older adults) participated. Acoustic measures of vowel contrast, variability, and duration were analyzed. RESULTS: Younger, but not older, speakers without impairment showed significantly reduced vowel contrast with noise masking. Relative to older controls, the AOS group showed longer vowel durations overall (regardless of masking condition) and a greater reduction in vowel contrast under masking conditions. There were no significant differences in variability. Three of the 6 speakers with AOS demonstrated the group pattern. Speakers with aphasia without AOS did not differ from controls in contrast, duration, or variability. CONCLUSION: The greater reduction in vowel contrast with masking noise for the AOS group is consistent with the feedforward system deficit hypothesis but not with the feedback system deficit hypothesis; however, effects were small and not present in all individual speakers with AOS. Theoretical implications and alternative interpretations of these findings are discussed.R01 DC002852 - NIDCD NIH HHS; R01 DC007683 - NIDCD NIH HH

A Cross-Linguistic Preference For Torso Stability In The Lexicon: Evidence From 24 Sign Languages

When the arms move in certain ways, they can cause the torso to twist or rock. Such extraneous torso movement is undesirable, especially during sign language communication, when torso position may carry linguistic significance, so we expend effort to resist it when it is not intended. This so-called “reactive effort” has only recently been identified by Sanders and Napoli (2016), but their preliminary work on three genetically unrelated languages suggests that the effects of reactive effort can be observed cross-linguistically by examination of sign language lexicons. In particular, the frequency of different kinds of manual movements in the lexicon correlates with the amount of reactive effort needed to resist movement of the torso. Following this line of research, we present evidence from 24 sign languages confirming that there is a cross-linguistic preference for minimizing the reactive effort needed to keep the torso stable