Language growth in verbal autistic children from 5 to 11 years.

To examine predictors and growth in language for verbal autistic and non-autistic children with/without low language from 4 to 11 years. Receptive and expressive language trajectories were compared in a community sample of 1026 children at ages 5, 7, and 11 years, across four groups: two autistic groups; one with and one without low language; and two non-autistic groups; one with and one without low language. Groups were delineated on baseline assessment at 4 years. Non-autistic and autistic children with low language had lower mean expressive language scores than the non-autistic typical language group (22.26 and 38.53 units lower, respectively, p < 0.001), yet demonstrated faster language growth across 5 to 11 years (p < 0.001 and p = 0.002, respectively). Both groups without low language had similar mean expressive language scores (p = 0.864) and a comparable rate of growth (p = 0.645). Language at 4 years was the only consistent predictor of language at 11 years for autistic children. Results were similar for receptive language in all analyses except there was no significant difference in rate of progress (slope) for the autistic with low language group compared with the typical language group (p = 0.272). Findings suggest early language ability, rather than a diagnosis of autism, is key to determining language growth and outcomes at 11 years in verbal children. Furthermore, children with low language showed developmental acceleration compared with same age peers.