• Phonetics and Speech Sciences
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• v.8 no.3
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• pp.79-90
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• 2016

The purpose of this study was to investigate the effects of stuttering severity on articulation rate measured from different types of utterances in preschool children who stutter. Participants were 40 boys who stutter (CWS) and age-matched 10 boys who do not stutter (CWNS). CWS were sub-grouped based on the severity of their stuttering: 15 mild, 13 moderate, and 12 severe. Utterances were categorized as "overall utterance" including all utterances that children spoke and "fluent utterance" which did not contain any disfluencies. Utterances containing abnormal disfluencies were categorized as "SLD utterance" for CWS. The results revealed no significant difference among groups in any type of utterance. There were significant positive correlations in articulation rates between utterance types. Stuttering severity was not a factor for characterizing the articulation rate of each type of utterance. Also, current findings suggest that articulation rate may not predict speech motor control ability in preschool CWS.

• Phonetics and Speech Sciences
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• v.13 no.1
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• pp.53-64
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• 2021

According to Demand and Capacity Model (DCM), external and internal environments influence the disfluency of children who stutter (CWS). This study investigated the effects of simultaneous changes in motoric and linguistic demands on CWS and children who do not stutter (CWNS). Participants were 4-6 years old CWS and CWNS. A sentence imitation task with changes in speech rate, utterance length, and sentence complexity was used to examine their effects on children's disfluency. When the utterance length changed, CWS showed more disfluency regardless of utterance length and as the speech rate changed, CWS showed more disfluency at fast speech rate than CWNS. When the utterance length and speech rate changed, at fast speech rate, CWS showed more disfluency in both utterances than CWNS. When sentence complexity changed, CWS showed more disfluency than CWNS in complex sentences. Changes in linguistic elements such as speech rate, utterance length, and sentence complexity affect disfluency in CWS, especially when they were exposed to faster, longer, and more complex sentences. This indicates that CWS are vulnerable to fast and complex speech motor control and language processing ability than CWNS. Thus, this study suggests that parents and therapists consider both the speech rate and the utterance length when talking with CWS.

• Phonetics and Speech Sciences
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• v.13 no.4
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• pp.101-114
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• 2021

The purpose of this study was to investigate the temperament characteristics associated with stuttering subtypes (persistent and recovered) over time and the relationship between those characteristics and stuttering severity. This four-year longitudinal study covered 41 preschool children who stutter (CWS) and 30 preschool children who do not stutter (the CWNS group). At the final visit, 27 CWS were classified as the Recovered group and 14 CWS were classified as the Persistent group. Using the Children's Behavior Questionnaire-Short Form, each participant's temperament characteristics were measured twice: at one year and two years after the initial visit. The three subscale scores (Extraversion, Negative Affectivity, and Effortful Control) and the 15 component scores were analyzed, and they were used for between-group and between-visit comparisons. The Persistent group showed a significantly higher Negative Affectivity subscale score at every visit than the Recovered and CWNS groups. Within this subscale, significant group differences were found in the 'Fear' and 'Anger/Frustration' components, demonstrating that the Persistent group scored higher than the Recovered and CWNS groups. There was no significant correlation between the subscale and component scores and the stuttering severity scores within the Persistent group at any visit. These results support the proposition that these two stuttering subtypes have different temperament characteristics; they also imply that temperament might be influenced by stuttering experience over time.

• Phonetics and Speech Sciences
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• v.13 no.4
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• pp.75-87
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• 2021

The purpose of this study was to investigate, longitudinally, interruption behavior which children who do stutter (CWS), children who do not stutter (CWNS) and their mothers and relationship with disfluency of children showed during interactions with their mothers. Subjects for this study consisted of 2-5 year old CWS (male 2 and female 4), an age-matched group of CWNS (male 3 and female 3), and their mothers. Frequencies of normal disfluency (ND) and abnormal disfluency (AD) in children group and frequency of interruption and simultalk duration in children and mothers group were measured two times (initial visit and 12 months later) over the course of one year. As a result, no significant difference was observed in frequency of interruption and simultalk duration both between two mother groups and between two child groups at initial visit and 12 months later. However, frequency of interruption increased significantly over the course of one year in CWS group. A significant group difference was found in frequency of interruption of mothers but, no significant difference was observed in simultalk duration of mothers at initial visit. In the CWS·mothers group, no factors were related with disfluency of children at initial visit and 12 months later. These findings suggest that interruption is not just negative behavior, and that reducing interruption should be considered in child·parent interaction therapy for CWS.