Most studies examining children's understanding of transitive sentences focus on the morphosyntactic properties of the construction and ignore prosody. But adults use prosody in many different ways to interpret ambiguous sentences. In two studies we investigated whether 5-year-old German children use prosody to determine participant roles in object-first (OVS) sentences with novel verbs (i.e., whether they use prosodic marking to overrule word order as a cue). Results showed that children identify participant roles better in this atypically ordered construction when sentences are realized with the marked, OVS-typical intonational pattern, especially in combination with case marking (Study 1). In a second study, we embedded these sentences into an appropriate discourse context. The results show that, even in the absence of any case marking, children understand participant roles when they are realized with the appropriate intonational pattern. These findings demonstrate that young children can use intonation to help identify participant roles in transitive sentences, at least in marked constructions such as the German object-first (OVS) construction. © 2011 Walter de Gruyter GmbH & Co. KG, Berlin/New York.