Abstract
This study contrasts sentence-level intonation in Acquired Language Disorder (ALD) and Developmental Language Disorder (DLD) with a view to providing insight into differential hemispheric involvement and lateralisation patterns using Hemispheric Specialisation Theory. Intonation tune assignment and fundamental frequency (F0) realisation using SFS version 1.51 were analysed across declarative sentences, wh-questions, declarative-form statements, polar questions, and reanalysed interrogative sentences. Participants comprised 18 people with ALD and 17 people with DLD from two tertiary health facilities, one rehabilitation centre and two government special schools in Ekiti State, Nigeria who completed a set of perception and production tasks targeting sentence-level intonation. The findings reveal a clear contrast between the groups. ALDparticipants exhibited relatively higher accuracy in selecting intonation patterns, particularly falling contours for declaratives and wh-question, and rising contour for polar questions. In contrast, DLDparticipants demonstrated prevalent reliance on level and obscure tunes with marked deficits in interrogative and pragmatically marked sentence types. Acoustic analyses further specified wide and differentiated F0 ranges in ALD, whereas DLD was characterised by compacted pitch ranges for falling contours and inflated terminal rises for rising contours. The results suggest that ALD involves disordered but patterns consistent with partial preservation of NE prosodic features arising from neurological injury, while DLD exhibits impairment beyondNE prosodic features. The study found that prosodic processing is differently impaired in the groups. It recommends the inclusion of control groups in further studies.
Keywords: Prosody; Language impairment;Hemispheric specialisation; Prosodic lateralisation; Fundamental frequency (F0)
DOI: 10.36349/sojolics.2026.v02i01.042
author/Bunmi Oluwaseun Esan
journal/Sokoto JOLICS 2(1) | June 2026 |
