Rhetorical questions (RhQs) are a complex phenomenon at the interface of pragmatics, prosody and syntax, which requires reasoning on intentions and goals, and which involves a mismatch between literal and intended meaning. In Italian, RhQs can be marked by optional particles and verbal morphology. We investigated when children aged 6-9 acquire the relevant patterns of optional modification and exploit them in the appropriate pragmatic context. In an elicited production study with 84 monolingual and 88 Italian-German bilingual children, we found that development in monolinguals was determined by age with a progression between 6 and 9 years, while bilingual development was influenced by proficiency in the heritage language and dominance more generally. These results are in line with Tsimpli's (2014) proposal that "very-late-acquired phenomena", especially interface domains, depend on their timing in acquisition. Unlike for other pragmatic phenomena, such as irony and conversational competence, there was no evidence for a bilingual advantage.