This paper proposes a new approach to the interface between linguistic form and speech acts. The basic idea is to rethink prevailing canonicity assumptions about the inventory of syntactic forms used to perform speech acts. I argue for a new concept of canonicity in that domain, which is based on the following claim: pragmatically unmarked versions of the major speech acts requests, questions, and assertions comply with the socio-pragmatic principle of ‘maximize politeness’. According to this principle, speakers try to minimize the risk of failure in achieving the relevant illocutionary goals of individual speech acts, and they can minimize that risk by using unambiguous linguistic forms that express politeness. I illustrate this account for unmarked forms of requests, questions, and assertions in German because in this language, the pragmatically unmarked versions of each of those speech acts can be signaled by dedicated particle elements (bitte ‘please’ in requests; denn ‘then’ in questions; and ja ‘yes’ in assertions). I claim that these particles are an overt realization of a syntactic head of a functional projection that encodes socio-pragmatic meaning in the left periphery of the clause. The paper sketches a unified syntactic analysis that holds across speech acts and that can potentially be extended to further phenomena of politeness marking in natural language.