Value added by assessing nonspoken vocabulary in minimally speaking autistic children

Purpose: There is a scarcity of language assessment tools properly adapted for use with minimally speaking autistic children. As these children often use nonspoken methods of communication (i.e., augmentative and alternative communication [AAC]), modification of traditional assessment tools is needed to capture the full range of their communicative repertoires. We modified the MacArthur–Bates Communicative Development Inventories (CDI) to explore how vocabulary size and composition are impacted by considering nonspoken, as well as spoken, expressive vocabulary (AAC-modified CDI: Words and Gestures).

Method: Our initial sample consisted of 16 minimally speaking autistic children, 3–9 years old, whose caregivers completed our modified CDI after taking part in an AAC intervention. Our final sample included 15 participants, after removing an outlier.

Results: Accounting for both spoken and nonspoken communication significantly increased participants' reported expressive vocabulary by an average of 14 words (z = −2.61, p = .009, r = .75). Verbs made up a sizable portion (13.3%) of vocabulary when accounting for all modalities, while nouns made up the majority (51.5%).

Conclusions: We demonstrated the value of including both spoken and nonspoken modalities of communication when assessing the expressive vocabulary of minimally speaking autistic children. Prior work has shown that minimally speaking autistic children's spoken vocabulary was prominent in verbs (i.e., contained proportionally more verbs than that of vocabulary-matched typically developing children). In our sample, which used a broader definition of minimally speaking, we found that the proportions of verbs and nouns were consistent with what has been reported for typically developing children with similar-sized productive vocabularies.