What gestures reveal about the development of semantic distinctions in Dutch children's placement verbs

Placement verbs describe every-day events like putting a toy in a box. Dutch uses two semi-obligatory caused posture verbs (leggen ‘lay’ and zetten ‘set/stand’) to distinguish between events based on whether the located object is placed horizontally or vertically. Although prevalent in the input, these verbs cause Dutch children difficulties even at age five (Narasimhan & Gullberg, in press). Children overextend leggen to all placement events and underextend use of zetten. This study examines what gestures can reveal about Dutch three- and five-year-olds’ semantic representations of such verbs. The results show that children gesture differently from adults in this domain. Three-year-olds express only the path of the caused motion, whereas five-year-olds, like adults, also incorporate the located object. Crucially, gesture patterns are tied to verb use: those children who over-use leggen 'lay' for all placement events only gesture about path. Conversely, children who use the two verbs differentially for horizontal and vertical placement also incorporate objects in gestures like adults. We argue that children's gestures reflect their current knowledge of verb semantics, and indicate a developmental transition from a system with a single semantic component – (caused) movement – to an (adult-like) focus on two semantic components – (caused) movement-and-object.