On Syntactic Realization Of Thematic Roles

The thesis attempts to initially formulate semantically defined verb classes within the formalism of typed feature structures so as to provide the lexical semantic representations for the verb classes that are needed in developing the models of linking within constraint-based HPSG. Then on the basis of the static mapping regularities that are explored between the semantic roles and syntactic arguments of the concerned verb predicators, a pragmatically involved dynamic linking approach is also proposed to handle the flexible mappings exhibited in some Chinese discourse data. It is strongly advocated in the thesis that, apart from the multiple inheritance hierarchies and typed feature structures which offer the tools for a successful theory of linking in static fashion, pragmatics, a distinct component of grammar needs to be invoked to map semantic roles into syntactic arguments in a right order.The thesis consists of six chapters. Chapter 1 surveys various notions of thematic roles and relevant linking theories. It begins with an examination of the traditional diacritic notion of thematic roles as a small set of un-decomposable primitives, and continues with a discussion of the thematic relation hypothesis, thematic hierarchies and the more elaborate conceptions of thematic roles. The thesis argues that an approach to linking based solely on a thematic hierarchy is vulnerable on several points, most notably with respect to the linking of causative verbs. The causal structure of the event denoted by a verb crucially affects the mapping between semantic roles and syntactic arguments. The assignment of direct arguments of a verb reflects the causal order among the participants in the event. Many theories employing thematic hierarchies also bring in additional mechanisms to account for this. Independent motivation for thematic roles and a thematic hierarchy, to the extent that it is presented in such theories, is examined and alternatives suggested. The view of thematic roles that emerges from more recent work both emphasizes this relational character and insists on more rigorous characterization of them in terms of lexical semantic entailments.Chapter 2 outlines the theoretical framework of the thesis, a combination of HPSG, proto-role theory and the model of multiple inheritance hierarchy of lexical semantic entailments. The first part of this chapter provides a brief review of Pollard & Sag's (1994) HPSG including its mechanism and grammatical nature. Some slight revision to the original model is suggested. The second part centers around Dowty's (1991) proto-role theory which claims that a small set of semantic entailments may determine the mapping between semantic roles and syntactic arguments. His proposal is evaluated and it is concluded that its shortcomings can be amended by incorporating an explicit representation of proto-roles within sort-resolved lexical semantic relations, modeled with typed feature structures proposed by Davis. Thethird part of the paper brings under its focus Davis's (1996) model of lexical semantic representation in his augmented proto-roles and hierarchy of lexical semantic relations, within which grammatically relevant semantic features are represented. In this part, Davis's revised model of proto-roles and their relevant sorted entailments hierarchy, the motivation of Davis's model and possible application in Chinese data are also examined.Chapter 3, started with a classification of Chinese verbs in terms of their semantic and sub-categorization features, spells out the constraints that statically hold between the lexical semantic representations developed in the previous chapter and the syntactic arguments on the ARG-S list, which represents a verb predicator's sub-categorization in HPSG. Both semantically and syntactically concerned standards of classification are evaluated. Though the theorem for English verb classification is heavily referred to, the uniqueness of Chinese verbs manifested in semantic and syntactic features is soundly taken into account. In this c...