The neural basis of language development and its impairment.

The neural correlates of early language development and language impairment are described, with the adult language-related brain systems as a target model. Electrophysiological and hemodynamic studies indicate that language functions to be installed in the child's brain are similar to those of adults, with lateralization being present at birth, phonological processes during the first months, semantic processes at 12 months, and syntactic processes around 30 months. These findings support the view that the brain basis of language develops continuously over time. Discontinuities are observed in children with language impairment. Here, the observed functional abnormalities are accompanied by structural abnormalities in inferior frontal and temporal brain regions.