本研究主要探討台灣學生英語的拒絕語言行為(refusal speech act)與美國學生之異同，並探討社會地位高低及啟始行為(initiating acts)兩個變數對語言行為之影響。此外在拒絕時,所使用的句法修飾(syntactic mitigation)及詞彙修飾(lexical mitigation)之類型與頻率,其所用的句型是否與美國學生不同, 以進一步探究學習者母語對其中介語(interlanguage)是否有負面移轉作用。 本研究採用質性及量化研究方法，研究對象為40位以中文為母語的大學學生, 40位英語為母語的美國大學學生,及40位學習英語為外語的大學學生, 各組男女各半。研究工具為言談填充測驗(Discourse Completion Test), 包含12個不同情境(4個請求, 4個建議, 4個邀請),藉此問卷收集受試者語言行為之表現。 本研究的主要發現如下：間接拒絕策略是最常被三組學生使用的拒絕行為。其次,社會地位高低及啟始行為(initiating acts)兩個變數下對三組學生語言行為有不同影響, 而以後者影響尤鉅。除此之外, 台灣學生的英語中介語的語用能力,不僅反映在句法修飾及詞彙修飾兩方面, 同時在直接拒絕行為也與美國大學學生有顯著差異。本文進一步發現學習者母語對拒絕行為之影響, 拒絕之語序及直接與間接拒絕策略的負面移轉作用。本論文並提出教學上之應用建議，讓學生英語學習更有成效。 / Refusals can be regarded as a pragmatic universal, but refusal performance varies with cultures and is constrained by factors like status and initiating acts. However, the relative weight of these factors placed on each type of refusal strategy varies from culture to culture, or even within the same speech community due to intra-lingual variations (Blum-Kulka, 1987). In order to find out the complexity of cross-cultural differences in the realization of this face-threatening act, we investigated refusal speech acts performed by native speakers of Mandarin Chinese, EFL learners and native speakers of American English with the variation of social status and initiating acts. In addition, we compared EFL learners and Americans on linguistic structures including common directive forms, syntactic and lexical refusal mitigation as well as types of errors in the interlanguage of refusals. We also observed evidence of negative pragmatic transfer in EFL learners’ performance in three main categories of refusal strategies and refusal sequences, and tried to explain the causes of the transfer. Three groups of subjects participated in this study: 40 native speakers of American English (NE), 40 native speakers of Mandarin Chinese (NC), 40 Chinese EFL low-intermediate proficiency learners. They were asked to react by writing in the format of discourse completion task (DCT), which consisted of scripted dialogues with the manipulation of the interlocutors’ social status and initiating acts. The results were coded based on the taxonomy developed by Beebe, Takahashi and Uliss-Weltz (1990), and were analyzed qualitatively and quantitatively. Results showed that indirect refusals were the most frequently used main strategy type in the three groups examined. The effect of social status and initiating acts affected the three groups’ performance to a different degree; initiating acts seemed to be a more decisive force in influencing groups’ refusal behaviors. In terms of refusal mitigation, we have found that significantly more syntactic mitigation like interrogatives, conditionals, conditional clause, etc. were employed by Americans to soften the force of refusals. However, similar to the findings in Chen (2006), EFL learners mainly limited their use of modality in their refusals on types of deontic and epistemic modalities whereas Americans were more flexible in using different kinds with the variation of context. Generally, EFL learners’ refusal performance exhibited deviations from native speakers’ norms. Therefore pedagogical implications were suggested which included that teachers should build up EFL learners’ linguistic knowledge, teacher-fronted talk can be supplemented by additional activities that broaden the range of speech acts and provide a broader opportunities for learners. Also, instructors should provide contextual information regarding the similarities and/or differences between L1 and the target language under the influence of social status. Types of initiating act should be included in EFL teaching so that students’ awareness of these social constraints could be activated and they can integrate such information to facilitate their interlanguage system.