This study concerns foreign language learners' motivational changes over a long period of time; it is an investigation of the learning histories of six learners who have achieved high proficiency in English. Unlike a large body of conventional foreign language learning motivational research, which has primarily been conducted using quantitative methodologies, this study employs two non-conventional approaches, a combination of learners' biographies and case study research. The primary purpose of the study is to holistically explore successful English learners' motivational trajectories and their learning histories in the Japanese context. To this end, foreign language learning motivation is conceptualized and illustrated as a dynamically changing construct that plays an important role in the process of foreign language learning. In the literature review, longitudinal studies concerning foreign language learning motivation and autobiographical studies and case studies that are relevant to this study are examined. The central research question is what motivational trajectories and learning histories these highly proficient learners have had, and how these learners have sustained their learning motivation over time and eventually achieved high proficiency while in an EFL (English as a foreign language) environment. The participants are six Japanese adults who have achieved high levels of English proficiency and who use English in their jobs. The design used in this case study involves both holistic and specifically focused analyses, by which each participant's learning history is collected through individual interviews. The author reports each participant's learning history, and the initial proposition concerning motivational change and salient motivational sources found in the participants' learning histories are collectively analyzed and discussed. Exploring the data concerning how the participants have maintained foreign language learning motivation resulting in the idea that sustained motivation is not always present in successful foreign language learning and that the key to success involves a cognitive change from a state in which motivation is present to one in which a more intentional psychological force, commitment to learning, develops. Based on this thought, a model illustrating the key to success in foreign language learning in the EFL context is presented. The results provide new, engaging, and important information to people who are seriously involved in foreign language learning in EFL contexts, where the majority of learners fail to attain high levels of foreign language proficiency after receiving years of formal education. / CITE/Language Arts

本文以敘事研究的方式，透過深入訪談，探討一位台灣語言學習者的自主動能（learner agency）與其學習環境之互動。經由敘事訪談（narrative interview）、開放式訪談、半結構訪談以及分析受訪者社群網站發表之文章，本論文意圖呈現台灣語言學習者在不同學習環境中如何表現自主動能。 本研究以受訪者Erin出國留學為分界，共三個階段：第一階段為受訪者出國前（2014/08/25），以敘事訪談（narrative interview）的方式，Erin完整呈現自我對英語的認知與語言學習歷程之掙扎。第二階段為Erin出國以後，藉由開放式與半結構訪談，描繪出Erin在國外求學的經驗，並更深刻探討過去的語言學習歷程。第三階段為Erin回國後(2015/09/17)，再次以敘事訪談的方式，Erin反思英國求學的經驗以及英語在其人生中扮演的角色。 本研究以vam Lier所提之自主動能的三個特色為分析框架，並推衍出兩項申明：其一，台灣英語學習者在正式的語言學習環境中面臨許多挑戰，但學習者仍有表現自主動能的空間，表現方式包括逃避或拒絕學習；其二，學習者若能沈浸於語言習得的環境（foreign language acquisition environments），極有可能脫離正式語言學習環境的框架而成為一個不同於以往的自己。本研究檢視學習者在不同的學習環境中如何展現自主動能，筆者期望研究結果可提供語言教師看待語言學習者一個新視角。 / Drawing on the concept of learner agency, a narrative inquiry was conducted in order to achieve an in-depth, qualitative understanding of the interplay between a Taiwanese learner's exert of agency and various contexts. The study was developed in three phases, and multiple number of interviews were the main instrument for data collection. The first interview was conducted in August, 2014, before the participant, Erin, headed for England to pursue a Master's degree. The following interviews documented her life experiences abroad and further explored her past language learning history. The final interview was conducted in September, 2015 after she came back to Taiwan, in which she reflected on her overall study abroad experiences and the role of English in her life. The findings delineated Erin's English learning story and her agency domestically and internationally. van Lier's proposal of core features of learner agency was used as the analytic framework to discuss Erin's story, and later two assertions were derived from the discussion: (1) Being an EFL learner in the Taiwanese formal educational context may involve many challenges, but the learner still has room to exercise his or her agency-even though this could mean avoiding or rejecting learning, and (2) Fully engaged in a foreign language environment, the learner is likely to break away from the limitations of formal English learning system. The study delineates a close examination on how the language learner interacted with various contexts and demonstrates several considerations TESOL practitioners can take. Based on the findings and the discussion, pedagogical implications as well as suggestions for future research are also provided at the end of the thesis.