Word type and modality in the emerging expressive vocabularies of preschool children with Down syndrome

Abstract

Background: Previous studies have explored the size and word type composition (nouns, predicates, etc.) of expressive vocabularies of preschool children with Down syndrome, both spoken and signed. Separately, overall preferences for modality of expression have also been explored. Aims: To extend previous findings by describing the relationships between expressive vocabulary size and both word type and modality of expression in the preschool period including changes to modality preference over time. Methods& Procedures: Mothers of 35 children with Down syndrome, aged 36-66 months and attending the same early intervention programme, completed a version -with both spoken word and sign options -of the New Zealand MacArthur-Bates Communicative Development Inventory (CDI): Words and Sentences. Most mothers completed the CDI on multiple occasions across the duration of the study. Completions (n = 114) were analysed cross-sectionally and longitudinally in terms of (1) word type relative to vocabulary size, (2) modality of expression relative to word type and vocabulary size, and (3) individual trajectories in vocabulary size and modality of expression. Outcomes & Results:(1) Word type relative to vocabulary size was similar to previous studies with a greater proportion of the SOCIAL words being present in the children's vocabularies throughout, followed by NOUNS, PREDICATES and CLOSED class words, with proportions converging as vocabulary sizes increase.(2) An initial spoken word preference for SOCIAL and CLOSED class words and sign preference for NOUNS and PREDICATES was found, with more spoken words in larger vocabularies overall. (3) Individual trajectories were highly variable and also revealed temporary points of regression in overall expressive vocabulary size in some children. Children who shifted from reliance on sign to predominantly spoken word expression did so at different ages and at different vocabulary sizes. At school entry, while most of the children used bothThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Variation in morpho-lexical development within and between diagnoses in children with neurodevelopmental disorders

“…The first section of the NZCDI is a checklist of 675 vocabulary items and, in the version used here, both a spoken word and sign option for each item allowing for three possible alternatives for each item (spoken word only, sign only, both word, and sign). The sign option was added to the NZCDI version used here in order to ensure that children’s full expressive vocabularies could be assessed irrespective of modality, and was particularly relevant for the children with DS in our sample who were routinely encouraged to use signed vocabulary as part of their early intervention program ( Foster-Cohen et al, 2022 ). The second section of the NZCDI includes a list of 107 items/questions: 5 irregular plural nouns (e.g., “feet”), 20 irregular past tense verbs (e.g., “came”), 14 overregularized nouns (e.g., “feets”), 31 overregularized past tense verbs (e.g., “comed”), and a 37 item section on complexity of expression which presents pairs of utterances in which the second of the pair is more complex than the first (e.g., “Daddy car” vs. “Daddy’s car”).…”