ABSTRACT

Purpose This study investigated stage-specific characteristics of speech processing in children with phonological disorders by comparing their performance on tasks representing the input, storage, and output stages of speech processing with that of children matched for chronological and language age.Methods Thirty children, aged between 4 years and 0 months and 6 years and 11 months, participated in the study. They were divided into three groups: one with phonological disorders, one matched by chronological age, and one matched by language age. Speech processing was assessed through three tasks: a phonetic discrimination task (input stage), a phonological representation judgment task (storage stage), and a nonword repetition task (output stage). Group differences were analyzed using one-way and mixed-design analysesof variance, while the relationships among the tasks were examined using Pearson correlation analyses.Results No significant differences were found between groups in phonetic discrimination performance, and there were no notable effects of task conditions. However, children with phonological disorder exhibited significantly lower performance on the phonological representation judgment task compared to chronological-age-matched peers, while their performance was comparable to that of language-age-matched children. In the nonword repetition task, the phonological disorder group performed significantly worse than both comparison groups, with performance declining for all groups as syllable length increased. Correlation analyses indicated a significant positive correlation between phonetic discrimination and phonological representation judgment, but only in the phonological disorder group. No significant correlations involving nonword repetition were found in any of the groups. Conclusions The findings indicate that speech sound difficulties in children with phonological disorders are more closely linked to weaknesses in the storage and output stages of speech processing, rather than deficiencies in basic phonetic discrimination. These results emphasize the importance of using stage-specific assessment and intervention strategies that focus on phonological representation and the demands related to speech output.