This paper draws on the following two conceptual premises: (A) it concretizes the Uniformity Hypothesis (Chomsky 2001: 2): "In the absence of compelling evidence to the contrary, assume languages to be uniform, with variety restricted to easily detectable properties of utterances." (B) It is couched in Obata et al's (2015) idea that the notion of syntactic parameters is reducible to the relative timing of syntactic operations, where the ordering itself is not specified by UG (cf. Biberauer & Richards' 2006 underspecification approach to UG and parametric variation). Specifically, parametric differences emerge not due to lexical differences of functional heads, but as a consequence of the different ways they enter syntactic environments, i.e., by set-Merge or pair-Merge. UG leaves the mode of their introduction underspecified and yields convergent outputs as long as the configurations and derivations they are part of are 3rd-Factor—and interface—compliant. This paper makes the novel proposal that the clausal functional lexical items v, T and C can (i) all be introduced by set-Merge (English-type), (ii) partly be formed by pair-Merge, giving <v, T>, and set-Merged C (German-type), and (iii) entirely be formed by pair-Merge, giving <v, T, C> (Japanese-type). Various empirical ramifications are explored.