「學什麼？」「如何學？」一向都是華語教與學的重要議題，但是「為什麼而學」的議題卻經常被忽略。分析「為什麼而學？」可顯示出學習者的語言學習需求何在，利用需求的內容，設計出符合語言使用情境的語言任務，讓學生藉由執行語言任務而習得語言，則能讓他們覺得所學的語言很實用，學習語言的需求也可以獲得滿足。本文即是由學習者語言學習需求的角度出發而探討任務型教學設計的研究。研究的觀察對象為越南台商公司的雇主與越籍員工，研究的方法以問卷、訪談、課堂觀察、討論與資料分析的方式為之。研究結果顯示，「任務」是語言教學的課程設計、成效評量的基礎，而學習需求的探討，則有利於設計與評估任務的有效性，二者有密切的依存關係。

Two important topics: ”What to learn?” and ”How to learn?” are frequently discussed in Chinese language education. However, we cannot ignore another also important topic, which is: ”Why do language learners learn?” The analysis of ”why” shows what the real needs of language learners are. Utilizing the knowledge of learners' needs, tasks of language can be designed properly to meet the context of communication. Learners acquire language via performing language tasks, which satisfies the learners' demands and makes them feel the learning practical and useful. This study is focused on the perspective of language learning needs in a task-based approach, from which a Mandarin teaching design has been made. The employers of Taiwanese companies in Vietnam and their Vietnamese employees are the objects of the observation in this study. The methods of research include questionnaires, interviews, classroom observation, discussion and data analysis. The result shows that tasks of language play important roles in curriculum design and assessment for language education, while the knowledge of language learning needs help evaluate the effectiveness of the teaching design.