The question of how and when children learn to associate clause type with its canonical function, or speech act, is currently unknown. It is widely observed that declaratives tend to result in assertions, interrogatives in questions, and imperatives in requests. Although such canonical links between clause type and speech acts are principled, they are known to be defeasible. In this corpus study, we investigate how parents talk to their children in the first years of life, and ask how their input might support this mapping, and to what extent it might pose difficulties. We find that the expected link between clause type and speech act is robust in the input, particularly between declaratives and assertions, both of which also occur most frequently. In addition, the non-canonical mappings that do occur are characterized formally, e.g., non-interrogative questions nearly always exhibit rising prosody, and non-imperative requests often contain a modal.

This paper analyzes the syntactic and interpretive components of a frequently used but understudied type of reduced why-question in English, referred to as Why-VP, as in why take Structure of Japanese? Using a substantial corpus of naturally occurring examples, it is argued that why in Why-VP is in fact a head which selects a null infinitival head, hosting in its specifier a structural subject, pro, and which in turn selects the familiar verbal projections (Voice/V). Previous work on Why-VP has suggested that it is necessarily elliptical and that it is necessarily rhetorical (conveying a preference). These assumptions led to proposals appealing to special compositional technologies. Analysis of the naturally-occurring examples, however, reveals that Why-VP retains a true interrogative interpretation. The syntactic structure proposed, in which Why-VP is an infinitival wh-question, predicts that it should have a modal interpretation, following Bhatt's (1999) analysis of covert modality in embedded wh-infinitivals. It is the modal interpretation characteristic of Why-VP that contributes to the rhetorical flavor, but that also allows for the genuine-question reading. Thus, we need rely only on independently available and familiar compositional mechanisms to understand the observed pragmatic effects.