Speech and language disorders in children with Down syndrome: A comprehensive review

Children with Down syndrome acquire language, but they do so on a timeline and through pathways that differ markedly from their typically developing peers. This research followed 74 children with Down syndrome and 82 age-matched typically developing controls from 12 to 60 months of age, documenting speech and language trajectories across receptive and expressive domains. Participants were recruited from six pediatric clinics across the São Paulo metropolitan area between February 2019 and November 2023. Language assessments were conducted every six months using the Brazilian adaptation of the MacArthur-Bates Communicative Development Inventories (MB-CDI) and the ABFW Phonology Test. At 60 months, children with Down syndrome achieved expressive language scores averaging 63.7% of age norms, compared to 97.8% for controls. Receptive language was comparatively stronger at 76.4%, though still significantly below the control group's 98.3%. The expressive-receptive gap widened progressively with age, reaching 12.7 percentage points by the final assessment. Phonological analysis revealed that children with Down syndrome used a more restricted consonant inventory, with persistent patterns of cluster reduction, final consonant deletion, and backing of alveolar sounds. Hearing status proved to be the strongest single predictor of language outcomes: children with recurrent otitis media scored 14.3 points lower on expressive measures than those with stable hearing. These results underscore the multifactorial nature of speech delays in Down syndrome and point to hearing management as a modifiable target for improving language outcomes.