ABSTRACT
Spanish expressive root sentences—exclamatives, optatives and degree exclamatives—can be introduced by both the complementizer que “that” and the complementizer si “if.” This fact provides privileged empirical evidence to investigate the meaning of these complementizers and their semantic contribution to the sentence. I propose that Spanish complementizers que “that” and si “if” form a binary system coding the semantic feature [±contrast]. This semantic feature, which is also present in some determiner systems, is responsible for the different meaning of que-expressives and si-expressives. Being both exclamative and optative expressive sentences, they imply a comparison between the proposition and its relevant alternatives. The complementizer si establishes a contrast between the proposition and the salient alternatives, whereas que adds the proposition to the other relevant alternatives. Exclamatives and optatives differ at the level where the comparison takes place, which is the discursive level in exclamatives and the modal level in optatives.
