Abstract：In 1980, a conference titled Loss of Language Skills was held successfully, which marked the establishment of the sub-field of linguistics called language attrition. Afterwards, the development of this new field attracts more and more attention from the whole academe. In the past, scholars preferred to study language acquisition. But nowadays, they have found out the significance of language attrition, because by investigating language attrition, they can have a better command of language acquisition. Language acquisition and language attrition are closely related with each other. So far, diversified studies on language attrition have been carried out by different study methods, such as the method of literature review, longitudinal case method, and so on. Some researches focus on the distinctions of attrition between different language elements, while some explore the attrition of a certain sub-system of the language, such as lexicon, morpho-syntax, phoneme, and so on. Because of its high attrition rate, lexicon which is a basic element of a language has been a main perspective for scholars to study the phenomena of language attrition.
The main purpose of the thesis is to figure out the relationship between the linguistic features of lexicon of English as a foreign language and the lexical attrition. By means of literature review, the studies as well as the theories both abroad and at home in the field of lexical attrition have been collected, summarized and analyzed. Finally, it is suggested that the linguistic features of lexicon of English as a foreign language including word class, length, frequency, and cognation do have a unique impact on the lexical attrition. The basic findings can be summarized as follows: (1) Word Class: Compared with the receptive word, the productive word is more susceptible to attrition. Besides, exclamation, preposition and irregular past tense of verbs are prone to attrition. (2) Length: In general, it will be more likely for longer words to suffer attrition. To be more specific, words with over four letters are more vulnerable to attrition than those with less than four letters. Additionally, words with only one syllable have the fewest attrition rates. But other words of more than one syllables hardly have any differences with each other from the angle of lexical attrition. (3) Frequency: The higher the word frequency is, the less attrition the learner will suffer from. (4) Cognation: English and Chinese are not cognate with each other. On account of so many differences between English and Chinese, the Chinese context will have a negative impact on the learners who study English as a foreign language in China.
The findings of the thesis also give us some useful implications for foreign language teaching in China. Firstly, teachers need to consolidate vocabulary by drill to help students pass the critical threshold period. Secondly, teachers need to arouse students’ interest and strengthen their motivation by improving vocabulary teaching strategies. Thirdly, teachers need to help students to form scientific learning habits, such as reviewing the words after a period of time and being sensitive to the words which are attrited easily.
Key Words: lexical attrition; feature; foreign language teaching
中文摘要：1980年， 语言技能磨蚀会议的成功举办，标志着语言磨蚀作为一个新的语言学的分支的建立。之后，该领域的发展吸引了越来越多学术界的关注。过去，学者们倾向于研究语言习得。但是现在，他们认识到了语言磨蚀的意义，因为通过研究语言磨蚀，他们能更好地掌握语言习得。因为语言磨蚀和语言习得的关系很紧密。到目前为止，通过各类方法，比如：文献综述，纵深个案分析法等， 人们正在开展多种多样的语蚀研究。有些研究者把重心放在研究不同语言成分的磨蚀差异上，而有些研究者则在探索同一个语言成分的语言磨蚀的特征，比如:词汇、形态、句法和音位等。词汇作为基本的语言成分之一，并且具有很明显的磨蚀速率，必将成为语言磨蚀的重点研究对象。
该篇论文旨在揭示外语（英语）词汇的语言学特征与词汇磨蚀的关系。该论文通过采用文献综述的方法，收集、 归纳、分析了国内外词汇磨蚀领域的理论和研究。最终归纳的研究表明：（1）词类：和接受性词类相比，产出性词类更易受到磨蚀。此外，感叹词、介词和动词的不规则过去式易于受到磨蚀。（2）词长：总体上，单词越长，越容易受到磨蚀。具体分析，含有四个字母以上的单词比含有四个字母以下的单词更易受到磨蚀。另外，只含有一个音节的单词磨蚀率最低。而多于一个音节的单词则几乎在词汇磨蚀程度上不存在差异。（3）词频：词频越高，单词越不容易受到磨蚀。（4）同源性：英语和中文是非同源语。由于英语和中文的许多差异，中文环境对在中国学习英语这门外语的学习者必定会产生负面的干扰。
该论文研究结果也对中国外语教学起到了一定的启示作用。第一，教师应通过操练来帮助学生强化词汇学习并最终使学生能通过关键阈时期。第二，通过改善词汇教学的策略，教师应能引起学生的学习兴趣和强化其学习动机。第三，教师应能帮助学生养成科学的学习习惯，比如定期复习，对易于磨蚀的词汇提高敏感度等。
关键词：词汇磨蚀；特征；外语教学
