Abstract:Since 1960s, many foreign scholars have shown great interest in code-switching and conducted researches on this interesting linguistic phenomenon from different perspectives. Some informative models have also been established to account for how language users to make code-switching in their daily communication. In our country, the research on code-switching started at the end of 20th century, but most of the studies are mainly in the form of introduction of others research results rather than the concrete investigation of the code-switching made by language users in Chinese context. With the development of IT technology and the Internet, people pay more attention to code-switching in online chatting. Nowadays, QQ has become the most popular social networking service in China, through which people can make online chatting very conveniently. One of the striking features of online chatting is frequent code-switching, which is caused by some social or psychological motivations.

　　　 In the present thesis, the online code-switching is classified in the following two ways: 1) interlingual code-switching--Chinese is substituted by letters, words and sentences in English and other languages; 2) interior code-switching and exterior code-switching. Based on such a classification, the thesis is intended to discuss the function of code-switching. It is found that code-switching can make the dialogue concise and simple, retains the idiomatic flavor and under certain circumstance, it can bring the functionality of emphasis and euphemism while highlighting the social status. The research is confined to the social group of college students living on campus, which constitutes one major limitation of the thesis. 

Key words: online chatting; Internet; code-switching

摘要:从上个世纪六十年代开始，一些外国语言学者便开始研究语码转换现象，相应地提出了一些基本的语码转换的模式。我国的语码转换研究起步于二十世纪末，但大多属于文献类研究，有关汉语与其他语言之间的语码转换的实证研究尚不多见。随着计算机技术和网络技术的飞速发展，网络会话中语码转换现象吸引了越来越多研究者的关注。在我国，QQ是最普遍和流行的网络聊天工具。在使用QQ聊天的过程中，不管是出于社会动因还是心理动因，不可避免地出现了中英文混合交替使用的语码转换现象。 

　　　本文致力于对利用QQ聊天软件进行对话中出现的语码转换现象，重点关注语码转换的形式，语码转换的内容，语码转换使用的情境，语码转换使用者期待获得的效果以及语码转换的实际功能。研究发现语码转换不仅使得对话简洁明快，保持原汁原味而且在特殊的情况下还能显示其强调和委婉的功能并且还会使得使用者身份获得一定程度的提高。

　　　但是本次研究存在的局限性也是十分明显的。语料的选取主要局限于在校学生的聊天记录，尤其是英语专业学生的网络聊天记录。这使得研究结果的普遍适用性和全面性稍有欠缺。

关键字： 网络聊天； 因特网； 语码转换