The present study joins the long-running debate about the semanticpragmatic 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 disentangle the controversial meaning of MUST-type predicates and then further theorized as a speech-act based framework of epistemic disambiguation.