1. Introduction 1.1 Research background Against the backdrop of globalization in economy, business communication is viewed as an important way to lead cross-cultural trades to a new level. Due to its ebb and flow as we can see, business communication is also considered as the main venue of cultural conflicts and exchanges. For China and the US with different cultural backgrounds, however, pragmatic problems are subconsciously ensuing from cross-cultural communications. In order to prevent communicators from losing temper for their lack of communication competence in business communication and greatly optimize the process of Sino-US communication, many scholars both at home and abroad have done researches on pragmatic failures and make professional studies on them from different perspectives. As a comparatively new branch of study in the area of linguistics, pragmatics is ”a general cognitive, social, and cultural perspective on linguistic phenomenons in relation to their usage in forms of behaviour” ( Verschueren, 2000:7). Cooperative principle which is developed by Grice in 1967 is the fundamental rule guiding conversational communication in business negotiation. Leech (1983) thinks of linguistics as the combination of ”grammar” and ”pragmatics”. He holds the view that a person#8217;s linguistic competence involves grammatical competence and pragmatical competence. Communication failures arise from lack of these two competence. Xiang Jixiu (2011:63) illustrates the phenomenon of pragmatic failures and further analyzes this phenomenon by applying the theory of cognitive context to investigate causes of producing pragmatic failures. However, few scholars discuss about causes of pragmatic failures in Sino-US communication from the perspective of adaptation theory, and there are still some limitations within the previous studies. To begin with, many scholars are dedicated to attribute pragmatic failures to cultural differences, negative transfer of mother language, cognitive context, etc. Other factors such as linguistic adaptation theory, pragmatic presupposition and relevance theory are not so often used to explore the cause of pragmatic failure. Furthermore, this thesis think of more than one perspective as its standpoints. Last but not least, with regard to pragmatic failure in business communication, some researchers not only ignore the subconscious interaction between the speaker and the hearer, but also overlook the preparation of the business communication. At this point, semantic and pragmatic presupposition, which help knowledge supplement and minimize the negative effects of pragmatic failure, relevance theory, which emphasizes the importance of cognitive environment, and linguistic adaptation theory, which supports constant subconscious interactions between the speaker and the hearer, meet the demand. 1.2 Research purpose Based on other scholars#8217; previous studies, this thesis is aimed at probing into pragmatic failures in Sino-US business communication from the perspective of adaptation theory in accordance with pragmatic presupposition and relevance theory. As far as I#8217;m concerned, as for Sino-US business communication, it involves both verbal and written communication. Thus, communicators are expected to adapt to both dynamic and static circumstances. On the one hand, one of obvious features of adaptation theory and pragmatic presupposition is dynamic in verbal communication. On the other hand, relevance theory (the hearer may not have the same knowledge background as the provider) can be applied in a business communication so as to raise communicators#8217; cognitive ability. Therefore, communicators are more likely to deduct implication in words in cognitive contexts with supplements of knowledge background. All in all, the adoption of pragmatic presupposition and relevance theory by communicators serves as an adaptation to the business communication context, in other words, the adaptation to the pragmatic presupposition and relevance theory, by so doing, business communication will reach a win-win scenario. 1.3 Significance of the research Practically speaking, it is noticed that China is on the track of chasing other economies in the world as Sino-US trades rapidly emerge, which is a great indication that Chinese companies appear like bamboo shoots after a spring rain. Alongside that, business communication followed by a large amount of foreign trades, Sino-US business communication in particular, is thriving beyond our imagination. As two big economies worldwide, China and the US are two important branches in commercial activities. In order to ensure that Sino-US business communicators avoid losses surging from potential pragmatic failures, this thesis is expected to analyze the causes of pragmatic failure and come up with reasonable suggestions by applying presupposition to investigation under the guidance of adaptation theory. Thus, business communicators are likely to embrace great success by reducing unnecessary misunderstanding and enhancing communicators#8217; ways of thinking. Theoretically speaking, to begin with, by taking characteristics of pragmatic presupposition and relevance theory into serious consideration, Sino-US business communication are possible to get rid of communication frictions and misunderstandings. What#8217;s more, under the guidance of adaptation theory, communicators are inclined to flexibly use pragmatic strategies which serve the interests of both sides. Last but not the least, amid business communication between China and the US, pragmatic failures which balk negotiations to carry out smoothly raise their ugly heads. Not even mutual sincerity can lead business communication to success from time to time. In that case, it is plausible to regard pragmatic failures in Sino-US business communication as a meaningful proposition of practical significance. 2.Literature review 2.1Overview of adaptation theory Adaptation theory, put forward by Jef Verschueren, a Belgian linguist, means adaptation to circumstances by language, or adaptation to language by circumstances, or mutual adaptation at the same time. Meanwhile, adaptation theory, feathering profound philosophical and psychological foundations, firmly believes that ”the one that can adjust to a new environment will be the winner” and stimulus-response theory(J.B.Watson, 1849-1936). Adaptation theory is also influenced by speech accommodation theory(Giles,1997) and functional view of Prague School(1926). Many action-oriented researches have been done by scholars. For instance, translators apply adaptation theory to the phenomenon of translation, from which the translator can translate materials in the mental world, the social world and the physical world. Besides, Xie Shanwang(2003) comes up with an idea that adaptation theory is suggested to be applied to foreign language teaching, which means it is better to make each student a direct hearer and strengthen interaction among students. 2.2Preview research at home and abroad Professor Qian Guanlian, a first person introducing adaptation theory, holds the view that the advent of adaptation theory observes functions of language in a comprehensive way rather than a subject parallel to morphology, syntax, semantics or phonetics. Pragmatics(Qian Guanlian, 1991) claims that adaptation theory involves five aspects: objects of linguistic adaptation, linguistic levels of adaptation, stages of linguistic adaptation, degree of consciousness and adaption strategy. In 2000, Qian Guanlian further explores the theoretical framework of adaptation theory. Alongside that, Understanding of Pragmatics(He Ziran Yu Guodong, 1999) overviews the main theories and problems of pragmatics and then systematically introduces theoretical framework and advantages of adaptation theory. Zhang Yanjun discusses the possibility of adaptation theory being complementary to cooperative principles in Cooperative Principles in Adaptation Theory(Zhan Yanjun,2009). Adaptation Theory and Relevance Theory--A comparison between two pragmatic views (Chen Chunhua,2003) briefly makes an contrast between relevance theory and adaptation theory and deducts the merits and demerits. As a conception of biological evolutionary theory, adaptation is applied to pragmatic research as a perspective, as a result, adaptation theory which is first put forward by Pragmatics as a Theory of Linguistics Adaptation(Jef Verschueren,1987) emerges, and is then illustrated by Understanding Pragmatics(Jef Verschueren, 1999). Adaptation theory can be developed into four aspects to explain usage of language: contextual correlates of adaptability, structural objects of adaptability, dynamics of adaptability and salience of adaptability. The essence of adaptation theory lies in dynamics of adaptability, which means context should interact with language structure so as to lead to utterance meaning. The choices of language is expected to be aligned with specific context and language structure. No matter it is verbal or written, it is of importance for the speaker to take hearer#8217;s cognitive ability into consideration. Verchuereen (2000:67) argues that these four angles of investigation can be seen as necessary ingredients of an adequate pragmatic perspective on any given linguistic phenomenon. Verschueren(2000:7) claims adaptation theory to be”a general, cognitive and cultural perspective on the linguistic phenomenon in relation to their usage”. Wittgenstein summarizes adaptation theory into four views of research: making choices, variability, negotiability and adaptability. That is to say, the process of the usage of language is the process during which language users, driven by language structure and communicative intention, continuously make choices. The range of choices of language is variable and language users need to negotiate constantly in the course of choices. Adaptability, which is the most significant, plays a role in choosing negotiable languages and strategies to meet both demands. References Barry, B. Oliver, R, L. (1996）. Affect in Dyadic Negotiation: A Model and Proposition[J]. Organizational Behavior and Human Decisive Process.22-24. Beamer, L.Varner, I.(2008). Intercultural communication in the global workplace. Boston:McGraw-Hill Irwin. Holmes, J. (2001). An Introduction to Sociolinguistics. Pearson Education Leech,G. (1983). Principle of Pragmatics[M]. London: Longman. Thomas, J. (1983). 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Outline 1Introduction 1.1 Research background 1.2 Research purpose 1.3 Significance of the research 2 Literature review 2.1 Overview of adaptation theory 2.2 Overview of pragmatic failure 2.3 Previous research at home and abroad 3 Cross-cultural analysis of pragmatic failures in Sino-US communication 3.1 Pragmatic failure in Sino-US business communication 3.2 Problems to be noticed in Sino-US business communication 3.3 Causes of pragmatic failure 3.4 Remedies for pragmatic failure 4Conclusion