Acoustic analysis on stop consonants in fluent reading speech of adults who stutter

This study investigated whether adults who stutter and normal adult speakers differ in the production of stop consonants in fluent reading of Chinese Putonghua.Voice onset time(VOT) was measured and the spectral moments at the stop burst were calculated for the stutterers(both before and after the speech therapy) and for the nonstutterers.The statistical results showed that there were no significant differences in VOT between the nonstutterers and stutterers either prior to or after therapy,although the mean VOT of the stutterers was slightly greater than that of the nonstutterers.The results also indicated that both the place of articulation and the subsequent syllabic final exhibited an influence,to a greater extent,on VOT for the stutterers.In the spectral domain,the spectral mean of the stuttering participants before therapy was significantly different from that of the normal participants,whereas the group difference became insignificant after the therapy session.The smaller spectral mean for the stutterers might be interpreted as a more posterior occlusion in the oral cavity when producing alveolars and velars.In addition,productions of the stutterers scattered with a wider range in the space of spectral moments.Furthermore,the smaller main effect of syllabic finals on the mean spectral frequency of the burst suggested that the stutterers exhibited weaker anticipatory coarticulation than the nonstutterers.