The main purpose of this thesis is to find out the economic factors that contributed to the successful promotion of Mandarin during martial law period, and serve as a reference for future language planning. Taiwan used to be ruled by Dutch, Koxinga, Qing dynasty, Japan, and the Republic of China (ROC) government. Thus, Taiwanese society gradually becomes multiethnic, multicultural, and, to my greatest concern, multilingual. Each ruling power had tried to impose different degrees of language policies on Taiwan, particularly Japan and the ROC government that were eager to establish an official language. Eventually, the successful popularization of Mandarin is overwhelming. A number of theories and materials regarding the relationship between language and economy have been reviewed. First of all, it is argued that language could be objectified and valued. Thus, different language varieties contain different values. Second, according to rational choice theory, people make choices that would maximize their benefits. The implication is that people choose to learn a certain language variety that benefits them most. Third, as an economy becomes more and more advanced, linguistic diversity might be reduced. The ethnolinguistic groups, language varieties, and language history of Taiwan are also discussed. There are four major ethnolinguistic groups in Taiwan: Hoklo, Hakka, aboriginal people, and Chinese Mainlanders. As for language varieties, Hoklo, Hakka, Mandarin, Taiwan Guoyu, and aboriginal languages are separately dealt with. The language history of Taiwan is divided into the evolution of spoken and written language of Taiwan. Then, the economic value of each language varieties in Taiwan during martial law period is assessed. The result is that Mandarin possessed the highest economic value. Besides, some features of economic development, such as structural change, the emergence of social classes, the desire to gain upward social mobility, expansion in education, and examination systems that favored Mandarin, also facilitated the spread of Mandarin. And through a comparison between the Japan-led and ROC-led island-wide language directives, this thesis argues that political factors alone could not sufficiently explain the successful promotion of an official language. Economic factors must be taken into account as well. Finally, some suggestions are proposed for the maintenance and revitalization of Hoklo, Hakka, and aboriginal languages.

臺灣Favorlang人作為研究主體的傳統，已綿延300餘年不輟，其間對於南島民族語言、文化研究的啟發，有著相當重要的貢獻。 Favorlang人身為荷蘭時代重要族群關係成員之一，除了累積殖民地對待異民族的經驗，留下的相關資訊，更成為歐洲學界理解窺探遙遠東方的窗口。本文首先討論相關定義，分類整理Favorlang人的研究史，舉其大要並詳述文獻背景，並且說明研究方法論的取向與研究角度的意義，提出對未來研究的期許和可能發展方向，可供進一步討論。 本研究運用荷蘭東印度公司檔案文獻，討論有關Favorlang的關鍵問題，最重要的諸如「Favorlang之位置」，以及「荷蘭時代資料」如何和其後的資料互相連結，從檔案對校出發，揭開了許多歷史的面紗；尤其本文對於17～18世紀荷文、漢文文獻的充分引用，找出許多記載矛盾的問題，試圖結合荷蘭時代與其後的各種漢文史料，重建一個「沒有歷史的臺灣原住民族群」在十七世紀的樣貌，重新思考各種文獻的解釋量度，意欲發掘「歷史—民族」研究方法論上更大的可能性，希望能為Favorlang研究打下一份基礎。