I think it should be very limited. Maybe a little bit of native language at the beginning and end of the class period, or if some explanation is needed that is far beyond the vocabulary of the students, but only rarely.
Related to this would be translanguaging. If a teacher is proficient in both languages, using the learners' native language to help them understand some complex concepts, such as grammar rules, would be beneficial for the students.
Code-switching has been an evolving topic since the bilingualism blooming in linguistics milieu. However, practitioners or experts have contrastive views regarding
its use in classroom setting. While the proponents believe that the presence of code- switching in one side is considered as an asset to teach language, the opponents see it is as merely an obstacle to achieve learning goal that is to acquire target language. Code-switching serves many functions for both teacher and students yet it is still employed. Despite the pro and cons of the code-switching, this research aims to show the perspective of both teacher and students towards code-switching and functions it serve in EFL classroom setting. This research used qualitative descriptive approach and the data were taken from the informants of English department in one of university in Surakarta to explore whether the use of code-switching in EFL classroom was seen as beneficial tool. It begins by the general view of EFL use in everyday classroom. This current study found that code-switching was preserved as benefits as it served some functions for teacher to convey material and for students to received material and communicate in classroom.
Based on learners needs, the teacher should decide whether to allow their use of code-switching in the classrooms. For my students, such use was allowed as I have noticed that it makes them more active and confident in using specific language structures. These same learners refused to speak the FL entirely before establishing the new routine where French and Mothertongue to be tolerated.
I would suggest such strategy to be used only with begginers to raise their confidence in using the target language and preparing them for the real world where such translanguaging is common currency(Garcia, 2009).
It is a part of bilingual education. If code-switching is towards the target language, it indicates that the learner is advancing further in L2. In the long run, it could even lead to a language shift.