학령전 말더듬 아동의 유창한 어절과 비유창한 어절의 조음복잡성지표 및 평균음운길이 특성

Abstract

Previous studies aimed at examining the association between phonetic factors and abnormal disfluency have primarily used Index of Phonetic Complexity(IPC) to assess phonetic complexity of words/phrasal words. The studies have reported that as phonetic complexity heightens, SLD(stuttering-like disfluencies) frequency tends to rise. The purpose of this study was to investigate whether the phonetic factors influenced the fluency breakdown of preschool children who stutter. Children’s speech samples during a story-retelling task were collected, and IPC as well as Phonological Mean Length of Utterance(PMLU) were analyzed to measure phonetic complexity. Research questions included (1) was there a significance difference in IPC according to types of phrasal words (SLD phrasal word, OD phrasal word, and fluent phrasal word)? (2) was there a significance difference in PMLU according to the types of phrasal words, and (3) were there any significant trends between IPC and PMLU in each type of phrasal words? Participants were 13 preschool children who stutter ranging from four- to five-year-old. To collect spontaneous speech samples, a story-retelling task from P-FA-II was used. The speech samples were transcribed phonetically, and disfluencies(SLD and OD) were analyzed. Phrasal words were classified into three types: phrasal word containing SLD(SLD phrasal word), phrasal word containing OD(OD phrasal word), and perceptually fluent phrasal word(fluent phrasal word). IPC following Lee et al.(2004) and PMLU following Yoon et al.(2013) according to the types of phrasal words were analyzed and compared. Results were presented as follows: (1) there was a significant difference in mean IPC scores among types of phrasal words(F=16.46, p<.001). Post-hoc test(LSD) showed that the IPC score of SLD phrasal word was significantly higher than that of OD phrasal word(p=.045) and fluent phrasal word(p<.001). Moreover, the IPC score of OD phrasal word was significantly higher than that of fluent phrasal word(p=.004), (2) there was also a significant difference in mean PMLU scores among types of phrasal words(F=5.66 p=.010). Post-hoc test revealed that the PMLU score of SLD phrasal word was significantly higher than that of OD phrasal word(p=.026) and fluent phrasal word(p=.002). However, no statistically significant difference was observed in PMLU scores between OD phrasal word and fluent phrasal word(p=.672), (3) a significant positive correlation was found between IPC score and PMLU score only in SLD phrasal word(r=.649, p=.016). OD phrasal word(r=.462, p=.112) and fluent phrasal word(r=-.187, p=.541) showed no significant correlation between the two scores. This study suggested that phonetic complexity is a factor affecting the occurrence of SLD and can be one of factors describing the occurrence of OD. This proposed the necessity that SLD phrasal word as well as OD phrasal word should be included in analysis to identify the characteristics of disfluency of preschool children who stutter.