The present study joins the long-running debate about the semantic– pragmatic distinction of the three domains of epistemic modality, evidentiality, and factuality. In particular, this work aims at providing both a theoretical and operational framework to investigate what type of speech act is at stake when a speaker/writer alternatively decides to mark a proposition as an epistemic modal, an evidential, or a factual construction. In fact, three basic types of illocutionary force will be shown to determine the modal marking of a constative speech act: evaluational (EvF(p)), presentative (PrF(p)), and assertive (AsF(p)) force. This classification is based on a set of tests that can effectively address either grammaticalized constructions or pragmatic strategies, independent from the specificity of the item under enquiry. This approach is first used to disen- tangle the controversial meaning of MUST-type predicates and then further theorized as a speech-act based framework of epistemic disambiguation.