Amsterdam Brain and Cognition (ABC)

SMART Lecture by Courtenay Norbury (UCL)

Non-verbal cognitive ability does not influence rate of language in the first years of formal schooling

09June2017 16:00 - 17:30


The June SMART Lecture will be presented by Courtenay Norbury (UCL), with an introduction by Jeannette Schaeffer.


Non-verbal cognitive ability does not influence rate of language in the first years of formal schooling

The role of non-verbal cognitive ability in the diagnosis and development course of ‘developmental language disorder’ (DLD) remains controversial, despite recent recommendations that non-verbal ability should not be included in diagnosis criteria. A question of theoretical and practical import is whether non-verbal cognitive deficits yield slower rates of language growth, perhaps signalling limited biological potential for language change.


In this lecture Norbury will present data from SCALES, a population study of language development and disorder from school entry. SCALES employed sample weighting procedures to estimate growth in core language skills, including measures of vocabulary, grammar and narrative. A stratified subsample (n = 529) received comprehensive assessment of language, non-verbal ability, and behavioral difficulties at 5-6 years of age and 95% of the sample (n = 499) were assessed again at ages 7-8. Language growth was measured using both raw and standard scores in children with typical development, children with DLD, and children with language impairment associated with other developmental disorders.


Across the first three years of school there was strong individual stability of language (estimated ICC = .93). Linear mixed effects models highlighted steady growth in language (raw scores), and parallel growth in standard scores across all three groups. Adjusted models indicated that while non-verbal ability, socio-economic status and behavioural skills predicted initial language score (intercept), none influenced rate of language growth (slope).


From school entry, rate of language growth was remarkably similar in three groups of children with diverse language and cognitive profiles. During this developmental window, language growth was not influenced by non-verbal ability; neither group with language impairment showed evidence of substantially narrowing the gap with typical peers. Importantly though, those with non-verbal cognitive deficits did not fall further behind. Findings suggest limited potential to change language trajectories after school entry, though the potential for intensive, well-targeted interventions to accelerate growth in children with DLD remains to be tested.



Courtenay Norbury is Professor of Developmental Disorders of Language and Communication at Psychology and Language Sciences, University College London. She is the Director of the Literacy, Language and Communication (LiLaC) Lab and is a qualified speech-language therapist. She obtained her PhD in Experimental Psychology at the University of Oxford, working with Professor Dorothy Bishop on the overlapping language profiles that characterise autism spectrum disorder and ‘specific’ language impairment. Professor Norbury’s current research focuses on language disorders in a range of neurodevelopmental conditions and how language interacts with other aspects of development. She is leading a population study of risk for language disorder at school entry, with a particular focus on identifying common co-morbidities in a population cohort. She is also one of the joint editors of the Journal of Child Psychology and Psychiatry and a founding member of the RALLI campaign (

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Published by  SMART Cognitive Science