The term code-mixing is variously defined in different subfields of linguistics. Many studies of morphology or syntax use the term as a synonym for code-switching, the alternating use by bilingual speakers of two or more different languages within a single utterance (e.g. Kachru 1978, Muysken 2000).
Studies in psycholinguistics similarly definition code-mixing as "the transition from using linguistic units (words, phrases, clauses, etc.) of one language to using those of another within a single sentence" (Sridhar and Sridhar 1980). In contrast to Muysken's treatment of code-switching and code-mixing as synonymous, however, Sridhar and Sridhar differentiate the two, arguing that code-switching has pragmatic or discourse-oriented functions that may be absent in code-mixing.
Some recent work in sociolinguistics builds on this functional differentiation. Alvarez (1998) argues that formal code-mixing or language alternation should be treated as distinct from code-switching, defined in pragmatic or discourse terms.
- Alvarez, Celso. 1998. "From 'switching code' to 'code-switching': Towards a reconceptualisation of communicative codes." In P. Auer (ed.) Code-switching in Conversation: Language, Interaction, and Identity, 29-48. London: Routledge.
- Kachru, Braj. 1978. "Toward structuring code-mixing: an Indian perspective." International Journal of the Sociology of Language 16:27-46.
- Muysken, Pieter. 2000. Bilingual speech. Cambridge: Cambridge University Press.
- Sridhar, S.N. and Kamal K. Sridhar. 1980. "The syntax and psycholinguistics of bilingual code-mixing." Canadian Journal of Psychology 34(4):407-416.