Two children playingEarly language

Mastering developmental milestones related to speech and language during the first few years of life shapes later-life development, especially for cognition- and education-related outcomes1–4, while difficulties acquiring age-appropriate language, communication, and literacy skills have been related to multiple neurodevelopmental conditions5–10.

Children typically start to utter their first words between 10 and 15 months of age11. At around two years of age, they may produce between 100 – 600 words, and understand many more12. Each child embarks on its own developmental path of language learning, resulting in large individual differences. These differences can be partially explained by genetic factors13–17.

In the EAGLE project studying early language acquisition and performance, especially during infancy and toddlerhood, we aim to unravel the etiological mechanisms underlying language development to gain insight into its biology as well as early manifestations of speech, cognition, social behaviour and mental health problems. So far, we published two genome-wide association studies (see below).

We are always interested in additional cohorts with early vocabulary or other language-related measures! Feel free to contact us via email ( or


1. Bleses, D., Makransky, G., Dale, P. S., Højen, A. & Ari, B. A. Early productive vocabulary predicts academic achievement 10 years later. Applied Psycholinguistics 37, 1461–1476 (2016).
2. Duff, D., Tomblin, J. B. & Catts, H. The Influence of Reading on Vocabulary Growth: A Case for a Matthew Effect. J Speech Lang Hear Res 58, 853–864 (2015).
3. Bornstein, M. H., Hahn, C.-S., Putnick, D. L. & Suwalsky, J. T. D. Stability of Core Language Skill from Early Childhood to Adolescence: A Latent Variable Approach. Child Development 85, 1346–1356 (2014).
4. Lee, J. Size matters: Early vocabulary as a predictor of language and literacy competence. Applied Psycholinguistics 32, 69–92 (2011).
5. Geurts, H. M. & Embrechts, M. Language profiles in ASD, SLI, and ADHD. J Autism Dev Disord 38, 1931–1943 (2008).
6. Helland, W. A., Posserud, M.-B., Helland, T., Heimann, M. & Lundervold, A. J. Language Impairments in Children With ADHD and in Children With Reading Disorder. Journal of Attention Disorders 1087054712461530 (2012) doi:10.1177/1087054712461530.
7. Germanò, E., Gagliano, A. & Curatolo, P. Comorbidity of ADHD and dyslexia. Dev Neuropsychol 35, 475–493 (2010).
8. Peyre, H. et al. Relationship between early language skills and the development of inattention/hyperactivity symptoms during the preschool period: Results of the EDEN mother-child cohort. BMC Psychiatry 16, (2016).
9. Tager-Flusberg, H. et al. Handbook of autism and pervasive developmental disorders. (2005).
10. Ozonoff, S., South, M. & Miller, J. N. DSM-IV-Defined Asperger Syndrome: Cognitive, Behavioral and Early History Differentiation from High-Functioning Autism. Autism 4, 29–46 (2000).
11. Clark, E. V. First Language Acquisition. (Cambridge University Press, New York, 2016).
12. Fenson, L. et al. Variability in early communicative development. Monogr Soc Res Child Dev 59, 1–173; discussion 174-85 (1994).
13. Dionne, G., Dale, P. S., Boivin, M. & Plomin, R. Genetic Evidence for Bidirectional Effects of Early Lexical and Grammatical Development. Child Development 74, 394–412 (2003).
14. Verhoef, E., Shapland, C. Y., Fisher, S. E., Dale, P. S. & St Pourcain, B. The developmental genetic architecture of vocabulary skills during the first three years of life: Capturing emerging associations with later-life reading and cognition. PLOS Genetics 17, e1009144 (2021).
15. St Pourcain, B. et al. Common variation near ROBO2 is associated with expressive vocabulary in infancy. Nature communications 5, 4831 (2014).
16. Dale, P. S., Dionne, G., Eley, T. C. & Plomin, R. Lexical and grammatical development: a behavioural genetic perspective. Journal of Child Language 27, 619–642 (2000).
17. Hayiou-Thomas, M. E., Dale, P. S. & Plomin, R. The etiology of variation in language skills changes with development: a longitudinal twin study of language from 2 to 12 years. Dev Sci 15, 233–49 (2012).

37,913 parent-reported vocabulary size measures (English, Dutch, Danish) for 17,298 children of European descent were studied. Meta-analyses were performed for early-phase expressive (infancy, 15–18 months), late-phase expressive (toddlerhood, 24–38 months), and late-phase receptive (toddlerhood, 24–38 months) vocabulary.

Participating cohorts: Avon Longitudinal Study of Parents and Children (ALSPAC), Barwon Infant Study (BIS), Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Early Language in Victoria Study (ELVS), Generation R (GenR), Longitudinal Study of Australian Children (LSAC), The Western Australian Pregnancy Cohort Study (Raine), Twins Early Development Study (TEDS).

Main findings: The genetic architecture of early-life vocabulary changes during development, shaping polygenic association patterns with later-life ADHD, literacy, and cognition-related traits.

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Summary statistics

A genome-wide screen of expressive vocabulary in toddlers of European descent from up to four studies of the EArly Genetics and Lifecourse Epidemiology consortium, analysing an early (15–18 months, NTotal=8,889) and a later (24–30 months, NTotal=10,819) phase of language acquisition.

Participating cohorts: Avon Longitudinal Study of Parents and Children (ALSPAC), Generation R (GenR), The Western Australian Pregnancy Cohort Study (Raine), Twins Early Development Study (TEDS).

Main findings: For the early phase, one single-nucleotide polymorphism (rs7642482) at 3p12.3 near ROBO2, encoding a conserved axon-binding receptor, reaches the genome-wide significance level (P=1.3 × 10−8) in the combined sample.

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Lead analyst: Ellen Verhoef (

Lead PI: Dr. Beate St Pourcain (

Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands


Max Planck Society


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