Abstract: “Frequency effect” means that the more a certain item occurs in a text, the more easily it is recognized. Ellis (2002) claims that frequency is a fundamental mechanism and is critical in language processing. Nevertheless, the empirical studies on the effects of input frequency on language acquisition are still insufficient. Based on former studies, this study investigates how word frequency affects different levels of English learners’ acquisition of English words. The major findings are as follows: (1) The higher the frequency of English words is, the more easily the words can be remembered. (2) Under the same circumstances, the high-level learners can remember English words more easily. Therefore, word frequency is very important to English vocabulary acquisition.

Key words: frequency effect; word frequency; English vocabulary acquisition

摘要：频率效应是指某一事物出现的次数越多就越容易被人们所识别。Ellis(2002)提出了以频率为中心的二语习得理论，认为频率是语言学习的决定因素，在语言习得理论中占有不可替代的重要作用；但是在二语习得领域，对语言输入频率的实证研究还较少，尚缺乏足够的证据。因此，本课题在前人的研究基础上，以高、低水平英语学习者为研究对象，调查词汇出现的频率对英语词汇习得的影响。通过分析，本研究得出以下结果：(1)出现频率越高的单词越容易被记住。(2)在相同条件下，高水平的英语学习者更容易记住单词。由此可见，单词出现的频率对英语词汇习得具有重要的作用。

关键词：频率效应；单词出现频率；英语词汇习得