The use of students' mother tongue (MT/L1) in the second/foreign language classroom has been debated in language teaching theory and practice for many decades. Most language teaching methods advocate the use of the target language (TL) in the classroom. However, recent research has elevated the role of L1 in the classroom. This paper illustrates traces of the mother tongue in past and present debates to provide an overall picture of the changes and help researchers identify the gaps in this area.