Bilingual conversations often mix languages within a single exchange. Code-switching is the alternation between two or more languages or language varieties in the course of a conversation or even a single sentence.

Switches may mark identity, negotiate social distance, quote someone, or fill a lexical gap. Structural constraints limit where switches can occur; not every boundary between words is equally available. Community norms determine whether switching is celebrated, tolerated, or stigmatized.

Researchers distinguish code-switching from borrowing by looking at frequency, adaptation, and speaker awareness. Recorded corpora show that skilled switchers follow systematic patterns rather than random mixing. Education policy debates often misunderstand switching as deficiency rather than as bilingual competence.

• Alternation between languages in conversation
• Serves social, pragmatic, and lexical functions
• Constrained by structural and community norms
• Distinct from one-off borrowing