The paper seeks to review on the use of a first language or a mother tongue (L1) in a second or foreign language (L2) classroom. The report examines permissible frequencies, practical purposes and influential factors of the L1 employment in the L2 classrooms. The findings provide that (i) there are mixed results of L1 use among novice and experienced teachers or low-level and high-level students and among different language teaching approaches followed by (ii) three main categorized reasons facilitating the role of L1. | A literature review on using the first language in a second or foreign language classroom