Chapter One Introduction 1.1 Research Background 1.2 Objectives and Research Questions 1.3 Methodology 1.3.1 Data Source and Collection 1.3.2 Research Method 1.4 Outline Chapter Two Studies on Discourse Markers 2.1 Definitions of Discourse Markers 2.2 Studies on Discourse Markers 2.2.1 Semantic-Pragmatic Perspective 2.2.2 Syntactic-Pragmatic Perspective 2.2.3 Cognitive-Pragmatic Perspective 2.2.4 Soeiolinguistic Perspective Chapter Three Theoretical Framework 3.1 Relevance Theory 3.2 Linguistic Adaptation Theory 3.3 Relevance-Adaptation Model Chapter Four Cross-Linguistic Comparative Analysis on Categories of English and Chinese Discourse Markers 4.1 General Information of English and Chinese Discourse Markers in Public Speeches 4.1.1 General Distribution of English and Chinese Discourse Markers 4.1.2 Distribution of Categories of English and Chinese Discourse Markers 4.2 Comparative Analysis on English and Chinese Discourse Markers in Terms of Social Factors 4.2.1 Comparative Analysis on English and Chinese Discourse Markers in Gender 4.2.2 Comparative Analysis on English and Chinese Discourse Markers in Age 4.2.3 Comparative Analysis on English and Chinese Discourse Markers in Culture 4.2.4 Comparative Analysis on English and Chinese Discourse Markers in Social Status Chapter Five Cross-Linguistic Comparative Analysis on English and Chinese Individual Markers 5.1 Inferential Markers So and Yinci 5.1.1 Syntactic Features of So and Yinci 5.1.2 Features in Discourse-Pragmatic Functions of So and Yinci 5.1.3 Discourse-Pragmatic Functions and Syntactic Positions of So and Yinci 5.1.4 Speakers' Social Status and Syntactic Positions of So and Yinci 5.1.5 Speakers' Social Status and Discourse-Pragmatic Functions of So and Yinci 5.1.6 Combining Forms and Discourse-Pragmatic Functions of So and Yinci 5.1.7 Speakers' Social Status and Combining Forms of So and Yinci 5.1.8 Discourse-Pragmatic Functions of So and Yinci Within Relevance-Adaptation Model 5.2 Contrastive Markers But and Donshi 5.2.1 Syntactic Features of But and Donshi 5.2.2 Speakers' Social Status and Syntactic Positions of But and Danshi 5.2.3 Speakers' Social Status and Combining Forms of But and Danshi 5.2.4 Discourse Pragmatic Functions of But and Danshi 5.2.5 Speakers' Social Status and Discourse-Pragmatic Functions of But and Danshi 5.2.6 Discourse-Pragmatic Functions of But and Danshi Within Relevance-Adaptation Model Chapter Six Concluding Remarks 6.1 Findings and Implications 6.2 Limitations and Suggestions for Future Research References Appendix Ⅰ Sources of Data Appendix Ⅱ Discourse Markers in English Public Speeches Appendix Ⅲ Discourse Markers in Chinese Public Speeches