Alignment Development Is Not a Unitary Phenomenon: A Comparison of Speech Rate and Lexical Alignment in Children

Purpose: Conversational alignment, the phenomenon in which interlocutors exhibit similar communicative behaviors as one another, has been documented across many levels of communication. There has been a growing recognition of the need to understand the relationship between alignment at various levels. Here, we add to the body of literature by exploring the trajectories of alignment development at different communication levels in children. Using a conversational corpus in which early school-aged children demonstrated robust lexical alignment, we examined whether they also demonstrated similar patterns of speech rate alignment. Method: In this corpus, children ( n = 45) aged 5–8 years participated in two experimental sessions. In one session, they interacted with their parents (i.e., all mothers), and in the other, they interacted with the university students. During each session, the child engaged in two 10-min conversations: a problem-solving task and a play-based task. A total of 180 conversational samples were collected. Results: Linear mixed-effects models showed that the children did not align their speech rates across multiple contexts (i.e., different partners and tasks). Furthermore, there was no relationship between lexical and speech rate alignment. Conclusions: These findings suggest that alignment development in children is not a unitary phenomenon. Rather, alignment at different levels of communication may require different underlying skills and may be driven by different levels of automaticity.