Rethink the usage between L1 and L2 in the language classroom

Since the 20th century,the traditional linguists view that L1(mother tongue) only has negative impact on foreign language learning.In order to master the foreign language with high proficiency,it must be taught only through the target language in language classroom.This paper argues that the mother tongue both has the positive impact and negative effects on foreign language acquisition.In accordance with the related research findings in the field of second language acquisition since the 21st century,the essay discusses how to promote second language learning through the appropriate use of L1 in the language classroom.