Children successfully learn words through overhearing others engaged in verbal interactions. The current studies investigated the degree to which four-year-old overhearers are influenced by the response behaviors of addressees and by the interactional pattern of the speakers and addressees. It was found that while addressee responses on their own did not influence vicarious word learning (Experiment 1), they did influence vicarious word learning when they were part of the shared process of dialogue construction (Experiment 2). When speaker responses reinforced the label after disagreeing addressee behaviors, vicarious word learning was boosted. This suggests that, by the age of four, vicarious word learning involves dialogue comprehension and a pragmatic understanding of the joint construction of talk by conversational partners.