AbstractBy drawing on new verbal reduplication data of tentative constructions in Mandarin Chinese, this paper provides an interesting argument for the conception of phases and its corollary, Phase Impenetrability Condition (Chomsky 2001, 2004, 2008). In particular, it is observed that common lexical verbs are compatible with two templatic reduplication patterns whereas an independent light verb is only allowed to occur in one reduplicative form. We demonstrate that the noted discrepancies can receive a proper characterization by admitting the special status of spelled‐out light verbvand the phase it introduces in a phase‐based model of syntax‐morphology interface computation, where it is hypothesized that derivations must proceed cyclically and locally.