Code switching, that is, the alternative use by bilinguals of two or more languages in the same conversation, has attracted linguists’ attention and been studied from a variety of perspectives. Code-switching is a linguistics term denoting the concurrent use of more than one language, or language variety, in conversation. Multilinguals, people who speak more than one language, sometimes use elements of multiple languages in conversing with each other. Thus, code-switching is the syntactically and phonologically appropriate use of more than one linguistic variety. Speakers form and establish a pidgin language when two or more speakers who do not speak a common language form an intermediate third language. On the other hand, speakers practice code-switching when they are each fluent in both languages. Code mixing is a thematically related term, but the usage of the terms code-switching and code-mixing varies. Some scholars use either term to denote the same practice, while others apply code-mixing to denote the formal linguistic properties of said language-contact phenomena, and code-switching to denote the actual, spoken usages by multilingual persons. In the 1940s and the 1950s many scholars called code-switching a sub-standard language usage. Since the 1980s, however, most scholars have recognized it is a normal, natural product of bilingual and multilingual language use. In popular usage outside the field of linguistics the term code-switching is sometimes used to refer to relatively stable informal mixtures of two languages, such as Bangla or Hindi, or to refer to dialect or style-shifting, such as that practiced by speakers of African American Vernacular English as they move from less formal to more formal settings. Why is code-switching
Code-switching relates to, and sometimes indexes social-group membership in bilingual and multilingual communities. Some sociolinguists describe the relationships between code-switching behaviors and class, ethnicity, and other social positions In addition, scholars in interactional linguistics and conversation analysis have studied code-switching as a means of structuring talk in interaction. Analyst Peter Auer suggests that code-switching does not simply reflect social situations, but that it is a means to create social situations. Weinreich (1953/1968:73) argued that “the ideal bilingual switches from one language to another according to appropriate changes in the speech situation, but not in an unchanged speech situation and certainly not within a single sentence”. Speaker switches languages to achieve a special communicative effect. This paper will give a general review of the studies of code-switching and then focus on the grammatical constraints on CODE-SWITCHING. Studies of CODE-SWITCHING can be divided into three broad fields: sociolinguistic code-switching, psycholinguistic code-switching and linguistic code-switching.
Sociolinguistic approach to code-switching
Blom & Gumperz (1972/2000:126) introduced two patterns of CODE-SWITCHING, namely situational CODE-SWITCHING, in which the speaker switches languages according to the change of the situation and metaphorical CODE-SWITCHING in which the speaker switches languages to achieve a special communicative effect. They developed this concept and introduced another term ‘conversational CODE-SWITCHING’ (1982) which includes functions such as quotations, addressee specification, interjections, reiteration, message qualification, and personalization vs objectivization. Psycholinguistic approach to code-switching
Weinreich (1953/1968) classified three types of bilingualism according to the way in which bilinguals store language in their brains. 1) Coordinate bilingualism: the person who has acquired two languages in two separate contexts and the words are stored separately. 2) Compound: the person has acquired two languages in the same context. In this case, a word has a single concept but...