How can we explain children's understanding of the unseen world? Young children are generally able to distinguish between real unobservable entities and fantastical ones, but they attribute different characteristics to and show less confidence in their decisions about fantastical entities generally endorsed by adults, such as Santa Claus. One explanation for these conceptual differences is that the testimony children hear from others about unobservable entities varies in meaningful ways. Although this theory has some experimental support, its viability in actual conversation has yet to be investigated. Study 1 sought to examine this question in parent-child conversation and showed that parents provide similar types of content information when talking to children about both real entities and entities that they generally endorse. However, parents use different pragmatic cues when they communicate about endorsed entities than they do when talking about real ones. Study 2 showed that older siblings used discourse strategies similar to those used by parents when talking to young children about unobservable entities. These studies indicate that the types of cues children use to form their conceptions of unobservable entities are present in naturalistic conversations with others, supporting a role for testimony in children's early beliefs.