Young children use and comprehend different kinds of speech acts from the beginning of their communicative development. But it is not clear how they understand the conventional and normative structure of such speech acts. In particular, imperative speech acts have a world-to-word direction of fit, such that their fulfillment means that the world must change to fit the word. In contrast, assertive speech acts have a word-to-world direction of fit, such that their fulfillment means that the word must fit the world truly. In the current study, 3-year-olds understood this difference explicitly, as they directed their criticisms selectively to actors when they did not follow the imperatives of the speaker, but to speakers when they did not describe an actor's actions correctly. Two-year-olds criticized appropriately in the case of imperatives, but showed a more ambiguous pattern in the case of assertions. These findings identify another domain in which children's normative understanding of human activity emerges around the third year of life. (Contains 1 figure.)