Children's utterances from late infancy to 3 years of age were examined to infer their conception of knowledge. In Study 1, the utterances of two English‐speaking children were analysed and in Study 2, the utterances of a Mandarin‐speaking child were analysed – in both studies, for their use of the verb know. Both studies confirmed that know and not know were used to affirm, query or deny knowledge, especially concerning an ongoing topic of conversation. References to a third party were rare. By implication, 2‐year‐olds have a conception of knowledge that underpins their exchange of information in conversation. Implications for the child's developing theory of mind are discussed.