Social and Linguistic Correlates of Vocabulary Size in Autism: Overlapping Vocalization and Phonological Memory

This study sought to understand the wide variability in vocabulary development among autistic children by testing potential social and linguistic correlates of vocabulary size. The correlation between overlapping vocalization (i.e., an aspect of social interaction relevant to accessing input for vocabulary acquisition) and phonological memory (i.e., retaining linguistic sound sequences) with vocabulary size were examined in 22 autistic children (3 to 11 years old) engaged in a structured nonword repetition task. Overlapping vocalization and phonological memory were correlated with vocabulary size. Overlapping vocalization remained a significant predictor of receptive and expressive vocabulary size when controlling phonological memory and nonverbal cognition. Both social and linguistic factors were associated with receptive and expressive vocabulary size in autistic children engaged in a structured task.