People need a means which is language to play their role as a part of society in order to be able to interact and communicate. In all around the world we often find people that master more than one language. Indonesian people generally are mastering Indonesian, regional language and also, at least, one or even more foreign languages. The person who can speak and master more than one language, bilingual or multilingual, usually switches from one language to another in their interaction called code switching.  Key words: society, bilingual, multilingual, code switching.
