Researches of English language teaching (ELT) have focused on using mother tongue (L1) for years. The proliferation of task-based language teaching (TBLT) has been also occurred. Considerable findings have been made in the existing literature of the two fields; however, no mentions have been made in the combination of these two ELT aspects, i.e., the use of L1 in English as a Second and Foreign Language (L2) classrooms in which TBLT is adopted. Hence, this paper is to make an argumentation in the appropriateness of this combination. Firstly, terminologies related to Tasks and TBLT framework are shortly revised. Secondly, the controversies with for and against views in monolingual approach in second and foreign language teaching (L2 teaching) is mentioned. Lastly, the paper makes an argumentation on why and how to use mother tongue in a modern teaching model as TBLT.