Now days, English becomes one of compulsory subjects at all of schools in Indonesia (English as Foreign Language/EFL classroom). Supposedly, English classroom uses English as instruction. However, as multilingual society sometimes teacher and students find the situation that makes them speak Indonesian. The code-switching phenomenon has become very handy for teacher with students from diverse cultures. English teacher uses English in explaining the material and sometimes switch the explanation into Indonesian. According to Fakeye (2012) in Karen Marie Algarins- Ruiz’s thesis, code-switching is allowed in English teaching learning process but it should have positive attitude towards code-switching. It should not be seen as a sign of linguistic incompetence but valuable in the classroom. Code-switching should have intention of providing essential meaning to create lessons across the curriculum and work with text that are mostly written in English, learning new vocabulary participation, understanding of students in the learning process,
developing less formal relationship between participants, conveying ideas more easily, accomplishing lesson, and contributing to a “teachable” pedagogic resource.
The reason why the researcher wants to conduct a research
about English teacher’s and students’ code-switching is to find the types, functions, and the frequency, of classroom code-switching. The researcher conducts a descriptive-qualitative research. This study uses qualitative approach because the data are spoken. It was conducted at 10th grade of MA Darul Amanah Sukorejo in the academic year of
2015/2016. The researcher analyzes the use of teacher’s and students’ code-switching. The data collection are; observation, documentation and interview. The result of the study shows that the details of code-switching used by the teacher and students. In English teaching learning process
within 2x45 minutes, there are 79 utterances in English teaching learning process which are pronounced by teacher and students. There are three types of code-switching (tag code-switching, inter sentential
code-switching, and intra sentential code-switching). According to the type, there are 24 utterances of code-switching (30.7%). The number of tag code-switching are 6 utterances (25%), inter sentential code- switching are 12 utterances (50%), and intra sentential code-switching are 6 utterances (25%). Besides the types, the researcher also analyzed the function of code-switching. According to the functions, there are 47 utterances of code-switching from 79 utterances (60%). There are 9 functions in English teaching learning process, they are; explanation function appeared 9 times (19.1%), students helping each other function appeared 1 time (2.1%), moving activity/topic function appeared 2 times (4.2%), not knowing English counterpart function appeared 4 times (8.5%), checking for understanding function appeared 2 times (4.2%), teacher admonitions function appeared 1 time (2.1%), grammar translation function appeared 7 times (14.8%), grammar explanation function appeared 7 times (14.8%), and lapses function appeared 13 times (27.6). The recommendations are the English-Indonesian code- switching phenomenon should not be debatable according to the rules, reasons and functions are analyzed in this research; teacher and students should aware how to use language in English teaching learning, especially in the use of code-switching; and the researcher hoped the result of this research can help the readers to know that code-switching should be matched with the situation and condition.