Abstract：
Slang is one kind of language phenomenon which is highly colloquial and not standard. Although slang is only a small part of American English, it plays an important role in modern American life because it’s lively and succinct. It also reflects the US society and culture truly and lively. After introducing the definition, origin and history of American slangs, this thesis mainly analyzes the cultural connotation and the linguistic features of American slangs. In addition, the usage and development of American slangs are discussed. Finally, the conclusion is drawn that slang is the inevitable product of American social and culture’s development. It can not be separated from sub-culture groups. All the vividness and expressiveness of American slangs can not be possible without their unique linguistic features.

Key words： American slang; culture; linguistic features

摘  要：
俚语是一种高度口语化且不规范的语言现象。俚语虽然只是美国英语的一小部分，但因为它的生动和简洁，并真实而生动的反映了美国的社会和文化，所以在美国人现代生活中起着重要的作用。在介绍了定义及美国俚语的起源和历史后，这篇论文主要分析美国俚语的文化内涵和语言特点。另外，还讨论了美国俚语的用途和发展。最后，得出结论俚语是美国社会和文化发展的必然产物。它不能脱离亚文化群，并且所有美国俚语的活力与表现力是它们独一无二的语言特征。

关键词：美国俚语；文化；语言特征

1 Introduction
In foreign countries, the researches on American slangs have formed a relatively complete system. Flexner puts foreword that American's average vocabulary approximately has 10,000-20,000 and majority of them are less used. But at least 2 000 are slangs in the 10,000-20,000 words which probably accounts for 10%. And these slangs are very common in everyday use in America. Robert L, C also researches slangs’ uses. In China, many scholars have made a lot of researches on American slangs to introduce the American slangs’ characteristics, compositions and history. Dai Xiaobin and Wei Zhizhong explain the cause and existence of the slang. Yang Jinqiu remarks on the history and the development trend of American slangs and analyzed American slangs’ pragmatic features. Guo Jiuling says the slang is a mirror of culture. It is in the life of American subculture groups. Peng Yuanfeng and Sun Peijie discuss the development trend of the American slang. They consider that it plays an extremely important role in American modern life for communication and has upgraded from the unrefined language of the streets and marketplaces to a more common and stylish one. Wang Jinjie puts foreword that the prevalence of campus slangs in the United States has gradually become fashionable.