The purpose of this paper is to further the understanding of the syntax/pragmatics interface with reference to rare grammatical variables. The usage-based assessment of the pragmatic value of wh in situ in French shows that contrary to claims in the literature, the variable does not have a categorical pragmatic value in the contemporary period. It does historically have a categorically discourse-old, explicitly activated status, when it emerges as a new variable representing less than 1% of partial questions. Converging with current studies, an activation condition is proposed: rare emerging grammatical variables representing less than 1% of occurrences in the relevant category enter the grammatical system with an explicit activation value.