The Role of Language Aspects in the Assessment of Cognitive and Developmental Functions in Children: An Analysis of the Intelligence and Development Scales–2

The assessment of multilingual participants is challenging, as, for example, proficiency in the test language may interfere with test performance. We examined whether different language aspects (i.e., receptive and expressive language abilities, bi/multilingualism) contribute independently to the variance in scores on cognitive and developmental functions of the Intelligence and Development Scales-2 (IDS-2). The sample comprised 826 children aged 5 to 10 years living in German-speaking regions. Hierarchical regression analyses revealed that receptive language ability was significantly associated with almost all IDS-2 scores. Expressive language ability explained little additional variance, except for the intelligence composites, Verbal Reasoning (including subtests), and the basic skills subtests. Bi/multilingualism explained variance above language abilities only in subtests of Verbal Reasoning and verbal Long-Term Memory. Findings highlight the importance of considering language proficiency, particularly in tasks with high verbal demands, when assessing cognitive and developmental functions with the IDS-2 in participants at risk for linguistic disadvantages.