Abstract
Diplomatic language is a powerful weapon which is adopted by diplomats in international communications to develop good relations with other countries and defend the interest of the country. Effective diplomatic language needs to be decent and be able to show the inclination of the speaker on the discussed topic. These requirements make vagueness greatly preferred in diplomatic language. Successful diplomatic language can not only save face by its indirect and mild manner but also reveal the attitude of the speaker. The author tries to make classification of the vagueness that is embodied in the selected diplomatic examples and then probe on the pragmatic functions of vagueness in diplomatic language with the Cooperative Principle and Politeness Principle.

Keywords    Vagueness     Diplomatic Language   the Politeness Principle   the Cooperative Principle 
  
外交语言是捍卫一国利益的语言工具，是外交官在国际环境中进行有效联合和斗争的锐利武器。外交语言在大方、得体的同时还必须突出发言者的立场。外交语言的这些特点, 使得模糊语言在外交语言中得到了的大量的运用。成功的外交语言既能含蓄、委婉地保全双方的面子，又能表达出发言者的立场。本文拟在分析若干中英文外交实例的基础上，对外交语言中的模糊语进行分类归纳，结合礼貌原则和合作原则，对模糊语言在外交语言中的功能进行探讨，分析模糊语言在外交用语中的作用。

关键词    模糊语    外交语言   礼貌原则     合作原则

1 Introduction
Diplomatic language is a language used in diplomacy as a communicative channel to manage relations between countries. It distinguishes itself from daily used language with the features such as euphemism and vagueness. For recent years, many scholars, such as Guo Liqiu, Wang Hongli, Jin Guihua, have paid attention to the study of diplomatic language. They give much importance to the study of the stylistics, strategy, euphemism while less attention is paid to the study of vagueness in diplomatic language.

Diplomatic language is thought to be both precise and vague. (Guo Liqiu, Wang Hongli, 2002: 81-82) It is not difficult to understand that diplomatic language should be precise because accuracy is one of the features of effective communication. However, sometimes diplomatic language also needs to be vague. Probably the most likely reason for this is that the vague language helps achieve some special effect that can not be realized by the precise one. In recent years, vagueness is often studied from the perspective of pragmatic field.