Application Of Systemic Functional Theory To EST Text

In this dissertation I intend to characterize EST (English for science and technology) text, using Systemic Functional Theory as a framework for that discussion. Being a special text type for specific purpose, EST text has its own prototypical texture and patterns of information distribution. Through the dissection of some living EST texts, the features of EST text are vividly illustrated.This dissertation falls into five chapters. It begins with a brief discussion of the relationship between text and discourse in order to divert the direction of the study to written discourse analysis. Then the definition of discourse analysis and the purpose of the thesis are briefly discussed. The second chapter outlines the theoretical framework, namely, Halliday's systemic functional approach to discourse analysis and introduces the nature of EST text. The following chapter elaborates on the transitivity system in EST text and intends to reveal its different clause types as far as transitivity is concerned. The fourth chapter lays much more emphasis on the illustrations of living examples so as to demonstrate the features of thematic structure and information structure as well as cohesive ties. The fifth chapter is arranged specially to deal with the specific grammatical feature of EST text - "nominalization of processes". From the analysis of some examples, it is found that nominalization as a grammatical metaphor expresses the transference between process types. This can make us havebetter comprehension of EST text.The analysis offers a new prospect for further study and understanding of EST text. This dissertation particularly reveals that there are certain patterns and rules of information distribution in EST text, as well as the semantic relations between components in a clause. These all serve to the realization of coherence and cohesion of text. On this basis, the paper presents some effective ways to understand EST text. In this sense, my findings are not only expected to contribute to the development of the study of EST text but also benefit those who are interested in this field.