Supplementary Material for: Development and Validation of a Korean (L1)–English (L2) Speech Processing Task System for Children with and without Speech Sound Disorders

Introduction: Children with speech sound disorders (SSDs) often display heterogeneous underlying processing profiles that are not fully captured by conventional articulation assessments. To address this limitation, this study developed a computerized Speech Processing Task (SPT) system designed to evaluate multiple psycholinguistic processing stages such as speech perception, phonological awareness, representation, and motor programming. Methods: The SPT system was designed based on a psycholinguistic speech processing model and included ten subtasks: Discrimination Task (DT), Input Phonological Awareness Task (IPAT), Phonological Representation Task (PRT), Output Phonological Awareness Task (OPAT), and Nonword Repetition Task (NRT), administered in both Korean (L1) and English (L2). The system was computerized to facilitate automated scoring and analysis. Study 1 focused on item development and system implementation. Study 2 evaluated the content validity and internal consistency of the system using expert panel review and Cronbach’s α. Study 3 applied the SPT to typically developing children to examine their performance by task type and language. Results: All subtasks demonstrated satisfactory content validity (CVR > 0.80, CVI > 0.90) and high internal consistency (Cronbach’s α = 0.779–0.912). A repeated-measures ANOVA revealed significant main effects of language and task type, as well as a significant interaction between the two. Overall, participants showed higher performance on Korean tasks than on English tasks, with the exception of the DT. Among the subtasks, performance on the IPAT and NRT was relatively lower than on the other tasks. Conclusion: The SPT system showed strong validity and reliability, effectively capturing language and task-related differences in speech processing. By enabling parallel assessment in Korean and English, it offers a useful framework for profiling individual processing abilities and has potential applications in both research and clinical settings.