3. FIRST LANGUAGE USE IN TEACHINGMore than twenty years ago, a study conducted by Atkinson (1987) raised the debate on the role played by the L1 in classrooms. In light of the previous discussions, the educational system has seen a growing effort in promoting the use of the L1 as a tool to support the learning and teaching of foreign languages. To achieve maximum efficiency, we must understand how and when to integrate the L1 instrument into the learning and teaching process. 3.1 WHEN TO USE THE L1 IN THE CLASSROOM Before using the student's L1 in the classroom, teachers should know the criteria for deciding whether adopting the L1 will be the best choice. Cook (2001) suggests taking four factors into consideration: efficiency, learning, naturalness and external relevance. He further suggested that language teachers can decide when to use students' L1 by asking four questions: Will the L1 used generate a more effective outcome? Can the L1 really help the acquisition of a second or foreign language? Does the student feel more comfortable with instruction given in the L1? And will using two languages ​​create an authentic environment instead of a fake monolingual environment and help students master the practical use of TL in real-world communication? Littlewood and Yu's (2011) study, which examined the purpose for English teachers using the L1 in classrooms in Hong Kong and Mainland China, showed that teachers tend to use the L1 in the following circumstances: to test meanings and ensure understanding of TL, to build a friendly relationship in the classroom and to manage classroom behaviors (ibid, 2011). . Teachers often practice the use of L1 in numerous ways, but there are still some similarities with a framework of basic principles on...... middle of paper ......use of L1 and TL in the classroom. Some will be eager to collaborate, others will not. Therefore, teachers must overcome challenges in motivating students to use LT. This can be achieved by applying different teaching strategies such as different classroom organization, different teaching methods and implementation policies. With globalization and modernization, English as a global language is taught in many different contexts. Most English teachers are non-native speakers and teach English in their own country, where they share the same L1 with students. By knowing the set of advantages and shortcomings of using L1 in the classroom, along with techniques on how to use L1, it may be helpful for teachers to master the positive use of students' native language, and judicious use of L1 can even double the efficiency of the foreign language learning process.