Young Children Use the Discourse Marker "But" to Provide Clarifications in Everyday Conversations.

To communicate effectively, speakers must monitor and refine their utterances based on what their interlocutors know. Young children's use of the contrastive marker but offers a window into this ability. Using longitudinal transcripts, we examined how seven children (ages 2-5) used but to clarify messages in everyday conversations. We coded 1,446 utterances to identify clarifications addressing gaps in listener knowledge. Children rarely used but for clarification at age 2, with marked increases between ages 2 and 3. By age 3, children often used but to provide privileged information in response to adults' knowledge-gap cues. These findings raise questions about the role of conversational experience in the development of children's mentalising abilities.