Spoken vocabulary outcomes of toddlers with DD (Walters et al., 2021)

Purpose: Early intervention using augmentative and alternative communication (AAC) supports both receptive and expressive language skills. However, many parents and clinicians still worry that augmented language intervention might delay or impair speech development. This study aimed to (a) characterize and analyze the speech sound development of toddlers with developmental delay who participated in a parent-implemented language intervention; (b) examine the accuracy of speech sounds among toddlers who participated in an augmented language intervention using speech-generating devices and toddlers who participated in a traditional, spoken language intervention; and (c) examine the relationship between baseline factors (i.e., receptive and expressive language skills, vocal imitation, and number of unintelligible utterances) and the number of spoken target vocabulary words after intervention.

Method: This study used extant data from two randomized control trials of parent-implemented language interventions using AAC or spoken language. Out of 109 children who completed the intervention, 45 children produced spoken target vocabulary words at the end of the intervention. We identified and phonetically transcribed spoken target vocabulary words for each child and then classified them based on Shriberg and Kwiatkowski’s (1982) developmental sound classes.

Results: Children’s speech sound accuracy was not significantly different across intervention groups. Overall, children who produced more words had more speech sound errors and higher baseline language scores. Intervention group and baseline receptive and expressive language skills significantly predicted the number of spoken target vocabulary words produced at the end of intervention.

Conclusions: Participation in AAC intervention resulted in significantly more spoken target vocabulary words and no statistically significant differences in speech sound errors when compared to children who received spoken language intervention without AAC. Results support using AAC interventions for very young children without the fear that it will delay speech or spoken language development.

Supplemental Material S1. Missing data: Descriptive statistics between raw and transformed data.

Walters, C., Sevcik, R. A., Romski, M. (2021). Spoken vocabulary outcomes of toddlers with developmental delay after parent-implemented augmented language intervention. American Journal of Speech-Language Pathology. Advance online publication. https://doi.org/10.1044/2020_AJSLP-20-00093