Two types of wh-adverbials

This paper presents cross-linguistic arguments for distinguishing between two types of wh-adverbials: causal how, causal why, and epistemic why pattern together in taking an IP scope, functioning as operators, whereas method how, manner how, and purpose why pattern together in taking a VP scope, functioning as predicates of underlying events. For the former group, there is always a cause-effect relation underpinning their syntactic distributions across languages, which is semantically realized as a causative predicate taking two events as its arguments, i.e., a cause event and an effect event. In a causal question, it is the cause event that is bound by the question operator; in a resultative question, the effect event is bound instead. For the latter group, they surface as conjuncts of main predicates in Tsou, which in turn argues for a neo-Davidsonian treatment of adjunct association in syntax (Parsons 1990). The fact that a conjunctive how can be construed as either a manner/method question or a resultative question in Tsou further argues for an independent semantic module in grammar in the vein of Culicover and Jackendoff (1997).