Nonlinear evaluation of multisyllabic word productions of Persian-speaking children's phonologies in the context of social communication disorder intervention.

This study examined phonological skills in three Persian-speaking boys with social communication disorder (SCD; ages 3;7-5;1) across twelve sessions of a narrative-based intervention, with a focus on multisyllabic word production. Using a nonlinear phonological framework, performance was analysed through segmental accuracy (percentage of consonants correct, PCC) and whole-word measures, including phonological mean length of utterance (pMLU), proportion of whole-word proximity (PWP), whole-word accuracy (WWA), and correct syllables and consonants (CSC), alongside structural indices and phonological process analysis (SODA). Results showed that multisyllabic words were more vulnerable to prosodic and structural constraints than monosyllabic words, despite stable segmental accuracy (PCC > 90%). Omission, substitution, and cluster reduction predominated, indicating structural and prosodic challenges rather than articulatory imprecision. Whole-word and prosodic measures captured variability not reflected in PCC, demonstrating that multisyllabic analysis within a nonlinear framework provides a more sensitive and ecologically valid index of phonological organisation in Persian-speaking children with SCD.