Most diachronic studies dealing with finiteness are centered on the functional shift between main and dependent clause status. In contrast, this paper focuses on the acquisition of morphosyntactic finiteness features by a non-finite dependent construction that remains dependent, namely " finitization. " Givón (2011) suggests a theoretical distinction between " gradual " and " instantaneous " finitization, depending on whether the intermediate stage of the evolution involves mixed finite/non-finite morphosyntax or a variation between finite and non-finite clauses. The main findings of this paper are that, first, diachronic data from various languages attest to both these theoretical models, and second, that this distinction does not reside in the diachronic mechanisms at play (reanalysis or extension), but rather in the functional motivation for the change.