既有文獻指出，國語作爲一種官方語言，此語言能力可被視爲一種語言資本，有利於職業地位的取得。但要證明語言資本的影響，由於適用資料不多，除了蔡淑鈴(2001)的論文之外，相關研究極少。除了國語能力在職業取得上所扮演的角色之外，本文企圖檢視其他語言能力是否也可被稱爲語言資本，具有任何優勢？而不同的語言資本，在不同職業取得面向上各自扮演什麼樣的角色？此外，由於傳統分析方式在因果關係上的推論限制，本文也將利用工具變項估計法，針對語言的影響力做更可靠的估計。「台灣教育長期追蹤資料庫」(TEPS)涵蓋數種語言流利程度之豐富資訊，利用這份資料的獨特性，本分析得到以下幾項結論：一、國語能力對於脫離勞動階級、取得較高地位的職業確實有顯著正向影響；二、在相同教育程度下，外省族群職業地位較高，但國語能力解釋了大部分差異；三、控制教育及國語程度之後，客家族群具有顯著的職業地位弱勢；四、客家及外省人成爲小雇主的機會比閩南人來得低，但閩南語能力是解釋閩南族群之小頭家優勢的主因；外省、客家人一旦掌握閩南語，脫離自營或受雇身分、成爲小頭家的機會並無差異；五、一旦考慮到亟需人脈的「大雇主」身分，國語及閩南語都具有顯著正面影響；六、工具變項估計法得到的結果顯示，語言程度的實際影響力事實上要比傳統分析之估計值來得更大。

Mandarin has been the official language of Taiwan since 1945. Mandarin fluency is regarded as linguistic capital leading to other forms of capital, and as a stepping-stone to gaining desirable goods and positions. Accordingly, the literature contains no studies of the role of Taiwanese dialect (Minnangu) in occupational attainment, even though it is the primary dialect for the majority Minnan ethnic population. Existing studies suffer from simultaneous causality, resulting in biased estimates of language effects. Here we use data from the Taiwan Education Panel Survey (TEPS) to show that most differences between Minnan and non-Minnan Taiwanese are attributable to language rather than ethnicity. In addition to confirming the importance of designation as an "official" language, our results underscore the role of a prevalent dialect in social mobility. Our specific conclusions are (a) Mandarin fluency is beneficial for obtaining higher-status jobs, and accounts for the occupational status advantage held by Mainlanders; (b) Minnan Taiwanese are more likely to own and operate small firms, with Taiwanese fluency explaining much of this difference with Mainlanders; (c) dual Mandarin/Taiwanese fluency helps entrepreneurs develop medium and large firms; and (d) an instrumental variable analysis provides a better estimate of true language effect on occupational attainment. Our results confirm existing findings that the actual language effect is larger than those generally described by conventional analytical strategies.