This paper addresses the issue of how languages package the same features of meaning into morphophonological units of different sizes, giving rise to mismatches between surface form and meaning. A contrastive study of causatives in Japanese and Eastern Armenian shows that the same syntactic properties and semantic information are surfaced as a single word in Japanese while they are realized as a phrase in Eastern Armenian. The paper provides an account for the distinct surface realizations of similar causative constructions in these two languages based on interface relations between syntax and the PF and LF components. In particular, it is argued that the different surface realizations of predicates across languages can be captured by a language parameter that determines the spell-out to the PF interface.