Conversational turn-taking in families with children who are typically developing has been shown to positively impact their child’s receptive and expressive vocabulary scores (Gilkerson et al., 2018). However, limited research analyzes whether this relationship exists in children with developmental disabilities and limited speech ability. Research suggests that augmentative and alternative communication (AAC) facilities a greater vocabulary size in children with developmental disabilities (Romski et al., 2010), but it is unknown if conversational turn-taking impacts its success. This study examined the growth trajectory of conversational turn-taking throughout the AAC intervention. Additionally, it examined the impact of conversational turn-taking on the effectiveness of a 12-week augmented language intervention. The findings indicate that when participating in an AAC intervention, children and their communicative partners showed differing growth trajectories in conversational turns. Moreover, these children made greater gains in vocabulary size when exposed to larger amounts of conversational turns than children in spoken intervention.