The aim of this paper is to contribute to the discussion about the relationship between Foucault's analysis of discourse and the speech acts theory by opening a phenomenological view over both. We will focus on Foucault's last analysis of "free speech" or "parrhesy", which this author considers as "speech activity", in order to show that the very sense of the illocutionary force lies on the parrhesiastic activity. Such a force, we claim, is expressed in clasical terms as the rethorical virtuality of language, that is, as the possibility of self-constitution of the subject through language.