The ontogeny of child-directed communication: toddlers accommodate their gesturing to partner age

Human adults accommodate language use to the characteristics of their partners. A well-known example of linguistic accommodation is child-directed communication. When communicating with young children, we tend to use simpler vocabulary, longer structures, and more repetition. Even as toddlers, we adjust speech when communicating with younger partners, but when exactly this capacity emerges remains unknown. Prior to the onset of speech, gesture is a key channel of communication. We explore whether toddlers accommodate their prelinguistic gestures, in particular gestures’ complexity, temporal patterns, and prominence, to partners of different ages. Video data from 53 toddlers (13.7–36 months; 27 boys) were collected during free play in four groups from three Portuguese nursery schools. We first investigated whether toddlers used different gestural registers toward adults (n = 672 tokens) and peers (n = 923 tokens) and then focused on peer-directed gestures to assess whether toddlers adjusted gestural communication when addressing younger or older peers. Toddlers adjusted the complexity and temporal patterns of their gesturing to their recipient's age but did not change gesture prominence. Contrary to typical child-directed communication patterns, toddlers used a more diverse set with shorter gestures toward peers as compared with adults. However, within their peer group, toddlers communicated with younger peers at a slower pace and used a simpler set of gestures, in line with typical linguistic child-directed communication patterns. Our findings suggest that our ability to accommodate communication emerges before language is fully developed and is present in our use of prelinguistic gestures to partners of different ages.