Abstract As a tool of communication, speech is a kind of talk or address given in public, a prepared speech delivered to a special audience or on a special occasion。 Discourse analysis of speech is attracting more and more linguists’ attention。 In order to inspire people, the language of a public speech should be cohesive and complete which can appeal to the audience and be easy to understand。 Semantic coherence is an important principle measuring speeches and lexical cohesion is one of the important methods to build semantic coherence of discourse。75189

Based on the cohesion theory proposed by Halliday and Hasan, this paper analyses some lexical features of the public speeches and some commonly used lexical cohesion approaches and proposes that in a speech, the speaker can use different lexical cohesion approaches to achieve the desired results in order to improve the effectiveness of the speech。

Keywords: speech；cohesion theory；lexical cohesion 

摘要演讲辞是一种为特定的观众或在特定的场合公开发表的讲话。演讲辞的语篇分析吸引着越来越多的语言学家的关注。为了达到激励人心的效果，一个公开的演讲的语言需要完整，吸引群众，易于理解。演讲的语义连贯是衡量演讲的重要原则，而词汇衔接正是构建语篇语义连贯的重要方法之一。

本文以韩理德和哈桑的衔接理论为基础，分析了演讲辞的词汇特征及常用的词汇衔接手段，提出在演讲辞中可以使用不同的词汇衔接方法使演讲获得预期的效果，以帮助演讲者提高演讲的有效性。

毕业论文关键词：演讲辞；衔接理论；词汇衔接

Contents

1。 Introduction。1

2。 LiteratureReview2

2。1 Cohesion。2

2。2 Types of cohesion。。。3

3。 Lexical Features of the Speech。。5

3。1 Frequent changes of pronouns5

3。2 Use of rhetorical devices7

3。3 Combination of formal and colloquial language9

4。 Application of Lexical Cohesion in Speech。。。9

4。1 Use reiteration to stress intentions。。9

4。2 Use synonymy to avoid tedium。11

4。3 Use antonym to make images distinct。。。12

5。 Conclusion。。13

Works Cited15

1。 Introduction 

The study of language has a very long history。 Linguists have been studying it since the early of the 20th century。

With the development of global economy, human activities and international communication, public speaking has been infiltrating through many fields of the society。 It is an important form of style in western countries。 Also, it plays an essential role in many aspects of western life。 So many scholars have been interested in the characteristics of public speech。 They study it from many perspectives, such as structure, metaphor, function and interpersonal relation。 It has the characteristics of cramped construction, clear semantic and logical relationship, fluent and coherent discourse。 However, public speech usually employs a lot of cohesive devices so as to enlighten, encourage and convince people。文献综述

As we all know, coherence is one characteristic of discourse and the unit of language system。 The analysis of the phenomenon of repetition and form of parallelism in literary discourse is considered to be one of the earliest studies of discourse cohesion。 Halliday and Hasan make a great contribution to the development of cohesion theory。 In 1962, Halliday put forward the concept of cohesion for the first time, making it become a linguistic term from an ordinary word。 In 1976, Halliday and Hasan published Cohesion in English and put forward the concept of discourse cohesion。 The publication of this book marks the establishment of cohesion theory。 In the book he pides the cohesion into two types: grammar cohesion and lexical cohesion。 The study of cohesion theory gradually becomes popular。 Grammar cohesion includes reference, substitution, ellipsis, and conjunction。 Lexical cohesion includes reiteration, synonym, hyponymy and collocation。