codeswitching

Code-switching, or language switching, is the alternation between two or more languages or language varieties within a single conversation, clause, or sentence. It occurs in many multilingual communities and can serve multiple communicative functions.

Common patterns include inter-sentential switching (switching between sentences), intra-sentential switching (within a single sentence), and tag switching (insertions of a tag from one language into a sentence in another).

Several theoretical approaches explain why code-switching occurs. Poplack's equivalence constraint and free morpheme constraint describe structural boundaries that people navigate when mixing languages. The matrix language frame model posits a dominant "matrix" language that provides the grammatical structure, with embedded material from other languages. Other theories emphasize social meaning, such as audience design, identity, solidarity, or stance.

Code-switching is used for reasons including topic emphasis, quotation, humor, efficiency, or marking membership in a community. It can convey cultural identity, signal rapport, or manage discourse boundaries.

In education and policy, code-switching is debated: some see it as a resource to support comprehension and learning, while others advocate for monolingual instruction. Research examines cognitive effects, language development, and the social dynamics of multilingual settings.