jats:titleAbstract</jats:title> jats:pOur research examines the use of three stance adverbs of certainty (jats:italicactually, really</jats:italic> and jats:italicobviously</jats:italic>) across B1, B2 and C1 levels in the Trinity Lancaster Corpus (TLC). Particularly, we examined the occurrence of these adverbs in the subset of Spanish L1 speakers from Mexico and Spain. jats:italicReally, actually</jats:italic> and jats:italicobviously</jats:italic> were found to display a distinctive frequency of use across different proficiency levels and the different speaking tasks analysed. Dialogic tasks favoured a more frequent use of jats:italicreally</jats:italic> and jats:italicactually</jats:italic>, while jats:italicobviously</jats:italic> was hardly used. Qualitative analyses of the pragmatic functions of jats:italicreally</jats:italic> and jats:italicactually</jats:italic> revealed that there is an increase in the use of meanings to express hedging in jats:italicreally</jats:italic> and factualness in jats:italicactually</jats:italic> across the proficiency levels. Our research confirms the finding in jats:xrefGablasova et al. (2017)</jats:xref> that the type of speaking task conditions speakers’ repertoire of linguistic devices, although we argue that this conditioning operates on different levels.</jats:p>