This work provides an operational framework to study the unfolding of new factual propositions out of originally suspended-factual (Narrog 2009, Tantucci 2015b) statements during a speech event. In particular, this model is centered on the dynamic relationship between cognitive control (i.e. Kan et al. 2013) and epistemic certainty. A speaker/writer's epistemic inclination towards the factuality of a proposition P occurs throughout a text, either in the form of the assertive reformulation of an originally suspended-factual proposition P, or in the form of a presupposition trigger also turning P into a new factual statement. I refer to this phenomenon as textual factualization (TF) and I provide corpus data from the British National Corpus (BNC) to demonstrate it to be a frequent mechanism where an originally suspended-factual proposition [apparently P] is subsequently factualized both in written and spoken texts. I argue that TF instantiates as a form of interference/misinformation effect (cf. Ecker et al. 2015) as it triggers the qualitative alteration of an event memory by partially overwriting an original memory trace: from [apparently P] to [apparently P].