<p>The fact that speech acts serve to share commitments makes it possible to identify important preconditions for becoming a competent user of speech acts. I employ this assumption to investigate the development of prelinguistic, communicative competence in early childhood. To become competent users of speech acts, children must count as participants in normatively regulated joint activities. This includes being disposed to behave normatively, as well as knowing how to signal acceptance and rejection of candidate commitments which regulate those activities. Contrary to widespread opinions, I argue that by around 18 months of age children have started meeting these preconditions. I outline how they may get there based on studies about teasing and headshaking. To acquire the target competences, I argue, infants need not be able to conceptualize commitments or their contents, let alone reason about intentions and beliefs.</p>