Purpose: The aim of this research note is to encourage child language researchers and clinicians to give careful consideration to the use of domain-specific tests as a proxy for language; particularly in the context of large-scale studies and for the identification of language disorder in clinical practice.

Method: We report on data leveraged through the prospective Raine Study cohort. Participants included 1626 children aged 10 years (n = 104 with developmental language disorder [DLD] and n = 1522 without DLD). We assessed the predictive utility of common language measures including subtests of a standardised omnibus language assessment, non-verbal intelligence, and a domain-specific receptive vocabulary test.

Result: Children with DLD performed within the average range on a measure of non-verbal intelligence (z = -0.86) and receptive vocabulary (z = -0.38), as well as two out of the six subtests on the omnibus language assessment (zs > -1.50). The magnitude of the predictive relationship between language assessments and the likelihood of a child meeting criteria for DLD at 10 years was assessed using a logistic regression model, which was significant: χ2(8) = 16.91, p = 0.031. Semantic Relationships (OR = 1.13, CI = 1.04 - 1.23, p = .004), Formulated Sentences (OR = 1.07, CI = 1.01 - 1.13, p = .028), Recalling Sentences (OR = 1.20, CI = 1.15 - 1.26, p < .001), and Sentence Assembly (OR = 1.17, CI = 1.07 - 1.30, p = .001) were significant predictors of DLD.

Conclusion: Domain-specific language assessments, particularly those testing receptive vocabulary, may overestimate the language ability of children with DLD. Caution is urged when using such tests by clinicians and researchers, especially those measuring language skills of children at scale. Future directions for measuring the functional impact of DLD are presented.