Dizque has developed from the verb decir 'say' and the complementizer que, originating in a phrase meaning something like 'it is said that'. This article presents an analysis of this expression as used in contemporary Colombian Spanish based on a corpus of naturally occurring spoken and written data. It is shown that the range of use of dizque extends from functioning as a purely evidential marker, encoding reported speech and hearsay with a notion of doubt implied in some contexts, to a marker of epistemic modality, encoding extensions of the notion of doubt implied in its evidential use and nothing about source of information. This development is particularly interesting because it mirrors that seen for reported evidentials in languages that have a grammaticized system of evidentiality. This demonstrates that lexical and grammatical evidential devices may follow similar paths of semantic change, and suggests that this specific change, from reported speech to doubt, is representative of a cognitive phenomenon related to the nature of reported speech itself.