This experiment investigated whether children with specific language impairment (SLI), children with autism spectrum disorders (ASD), and typically developing children benefit from the incidental presence of orthography when learning new oral vocabulary items. Children with SLI, children with ASD, and typically developing children (n=27 per group) between 8 and 13 years of age were matched in triplets for age and nonverbal reasoning. Participants were taught 12 mappings between novel phonological strings and referents; half of these mappings were trained with orthography present and half were trained with orthography absent. Groups did not differ on the ability to learn new oral vocabulary, although there was some indication that children with ASD were slower than controls to identify newly learned items. During training, the ASD, SLI, and typically developing groups benefited from orthography to the same extent. In supplementary analyses, children with SLI were matched in pairs to an additional control group of younger typically developing children for nonword reading. Compared with younger controls, children with SLI showed equivalent oral vocabulary acquisition and benefit from orthography during training. Our findings are consistent with current theoretical accounts of how lexical entries are acquired and replicate previous studies that have shown orthographic facilitation for vocabulary acquisition in typically developing children and children with ASD. We demonstrate this effect in SLI for the first time. The study provides evidence that the presence of orthographic cues can support oral vocabulary acquisition, motivating intervention approaches (as well as standard classroom teaching) that emphasize the orthographic form.
Keywords: Autism spectrum disorders; Orthographic facilitation; Orthography; Specific language impairment; Vocabulary; Vocabulary acquisition; Word learning.
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