Effectiveness of Ultrasound-Aided Articulation Therapy for Children With Speech Sound Disorders

Inclusion Criteria: * Primary diagnosis of speech sound disorder with errors on lingual target sounds * Probe accuracy \<70% on the primary target sound at baseline * Cantonese as the first language * Hearing thresholds ≤25 dB in at least one ear, with no hearing loss exceeding 50 dB in the other ear * No syndromes or obvious dysmorphic features * No language disorders associated with biomedical conditions (e.g., cerebral palsy, autism spectrum disorder) * No oronasal fistula identified on oral examination or diagnosed velopharyngeal insufficiency Exclusion Criteria: * Presence of syndromes or dysmorphic features * Language disorder associated with biomedical conditions (e.g., cerebral palsy, autism spectrum disorder) * Hearing thresholds \>25 dB in one ear and \>50 dB in the other ear Planned surgical intervention during the study period