Validation of Korean-Index of Phonetic Complexity- Revision

Objectives: In order to examine whether the K-IPC-R (Korean-Index of Phonetic Complexity-Revision) is effective as a phonological evaluation index for children at the early stage of phonological development, this study verified the developmental and concurrent validity of the K-IPC-R. Methods: The K-IPC-R analyzing and scoring criteria were applied to measure phonetic complexity (K-IPC-R scores) and speech intelligibility (K-IPC-R proximity rates), and the differences among groups of 18 to 23 months, 24 to 29 months, and 30 to 35 months were examined by One-way ANOVA. In addition, the correlation between KIPC-R score and PMLU (Phonological Mean Length of Utterance), K-IPC-R proximity rate and PWP (Proportion of Whole-word Proximity). Results: First, The phonetic complexity tended to gradually increase with age. Significant differences were found between the groups of 18 to 23 months and 24 to 29 months, and between 18 to 23 months and 30 to 35 months. The K-IPC-R scores of all indices except for the form of the syllables increased with age. Second, it was found that children’s phonetic realization gradually approached adult target forms. Differences between the groups of 18 to 23 months and 24 to 29 months, and between 18 to 23 months and 30 to 35 months were significant. Third, there was a high correlation between K-IPC-R score and PMLU score, and between K-IPC-R proximity and PWP. Conclusion: This study is meaningful by demonstrating the validity of the K-IPC-R, which can conduct phonological assessments using an independent analysis method, and presenting the results of a study in children who are typically developing between 18 and 35 months.