Abstract:In recent years, discourse analysis based on Michael Halliday’s register theory as a new way of English learning has caught the attentions of scholars at home and abroad. However, literature works involved in these studies focused on few genres. Therefore, this article aims to explore the language features of four letters in movie Message in a Bottle from the perspective of register.

　　　Combined with the three variables of register, word choice, organization of language and language form of these letters will be analyzed. Through the analysis of field, tenor and mode, it can be easier to understand the language features as colloquial words, coherent language and diverse rhetorical devices in the letters. Therefore, register theory can be well applied in the analysis of discourse as it relates to language features. It may do some help on understanding and appreciating English discourse for Chinese students. 

Key Words: letters; register; language features

摘要:近年来，一种新的英语学习技巧——基于语域理论的语篇分析，受到了国内外学者的重视。然而，这方面的研究涉及的体裁比较少。因此，本文试图从语域的角度对电影《瓶中信》里四封书信的语言特色进行分析。

　　　通过结合这些信的语场，语式和语旨三个语域变量，就信中的词语选择、语言的组织以及修辞手法进行分析。通过对语场，语式和语旨的分析，这些书信的语言特色如通俗易懂的词汇，连贯的语言以及多样的修辞手法都可以得到很好的理解。语域理论与语言特色密切相关，因此它适用于语篇分析。希望这为中国大学生在英语语篇理解和欣赏方面有所帮助。

关键词：书信；语域；语言特色

　　　Halliday’s register theory considers that register is the functional variety of language. After analyzing the examples in this study, it can be summarized that the language using in these letters can be analyzed effectively from the perspective of Halliday’s register theory, and  the three variables of register relate to the language uses. From the perspective of field, the word choice shows the preference of simple and colloquial words. From the perspective of tenor, the first and the second person pronouns are used widely and in the letters and the combination of simple and complex sentences make the language more coherent. And from the perspective of mode, the letters shows that mode controls the form of language which is informal written form using plenty spoken words and two important rhetorical devices in these letters.