Information structure and the licensing of English subjects

Most approaches to argument realization in English are grounded in lexical semantic structure. While it is widely acknowledged that there is an intimate relationship between information structure and grammatical relations such as subject, there have been few attempts to formalize this observation. This dissertation proposes an interface model of argument realization in which information structure and lexical semantics jointly determine argument realization.;The model proposes two mechanisms through which information structure drives argument realization. In direct licensing, informational relations such as topic underlie the licensing of arguments. Though this is widespread in "topic-prominent" languages such as Mandarin, it is generally taken to be forbidden in "subject-prominent" languages such as English (Li and Thompson 1976). This dissertation demonstrates that direct licensing by information structure underlies a range of subject selection phenomena in English, and thus that languages fall along a continuum with respect to the availability of direct licensing. In the constructions that I investigate in depth, Topical Exclamatives and Copy Raising, the main-clause subject is licensed to function as a topic. This is formalized through a construction that changes the valence and the information structure requirements of the main predicate.;The second mechanism, resolution, has not been discussed in previous work. In resolution, information structure selects among two or more candidates for argument realization that satisfy the constraints of the lexical semantic system. This too is evident in English subject selection. I demonstrate that in the Instrument Subject construction, information structure resolves underspecified input from the lexical semantic linking system. In order to be realized as a subject, an instrument must be associated with a proposition that is activated in the discourse. This is implemented by a construction that pairs the linking of an instrument subject with specific informational constraints.;The constructions that underlie Topical Exclamatives, Copy Raising, and Instrument Subjects can be seen as two concrete components of the often-assumed, but sometimes nebulous-seeming link between subjecthood and information structure in English.