Aha-moments in interaction: Indexing a change of state in Polish

•Polish aha is used as a change-of-state token.•Prosody and sequential position distinguish three functions of aha.•aha indexes a change in informedness, now-understanding and revelation.

This paper focuses on the change-of-state functions of aha in Polish. Drawing on the analysis of data from ordinary and institutional conversations the paper identifies systematic patterns in the token's prosodic realization and its sequential position, which allow for distinguishing three different kinds of change-of-state signaled by aha. It will be shown that (1) a relatively plain aha, produced as a third-positioned receipt to question-answer sequences, indicates a change in informedness, while a prosodically accentuated ↓a↑ha:::, (2) uttered in response to elicited or unelicited elaborations, indicates now-understanding, and (3) produced as a post-expansion to an already possibly closed sequence, indicates revelation.