A Study on Disfluency Characteristics in Non-Stuttering Children for the Development of a Stuttering Prediction Test

Purpose : This study systematically analyzes the types and frequency of disfluencies in the natural speech of typically developing children. It aims to identify developmental patterns by age, providing foundational data to distinguish normal disfluency from pathological stuttering and to support the development of early screening tools. Methods : Participants included 21 typically developing children (ages 4, 5, and 6) in the Gyeongnam region. Speech samples were collected through free-play and book-reading interactions. One-hundred utterances were obtained from each child and classified into normal disfluency (ND) and abnormal disfluency (AD) types for statistical analysis. Results : The total disfluency ratio was highest at age 4 and decreased with age, though differences across groups were not statistically significant. Within each age group, the ND ratio was significantly higher than the AD ratio, particularly for 4- and 5-year-olds. Regarding specific types, part-word repetitions increased with age, peaking at age 6, while interjections and incomplete phrases were most frequent at age 4 and decreased thereafter. Word and phrase repetitions were highest at age 4, dipped at age 5, and slightly increased at age 6. Revisions and hesitations remained infrequent across all ages. Notably, no prolongations or blocks were observed in any group. Conclusions : Typically developing children exhibit significantly higher rates of normal disfluency compared to abnormal disfluency. While total disfluency showed a descriptive decline with age, specific types demonstrated distinct qualitative shifts. These findings provide essential baseline evidence for understanding normal speech development and creating assessment tools for the early prediction of stuttering.