When monolingual speakers move from formal to informal modes of speech within…

Concept: Code-switching is the sociolinguistic term for alternating between codes — separate languages, dialects, or registers/styles — within a single communicative event, without changing the underlying language. It covers bilingual speakers moving between two languages as well as monolingual speakers shifting between formal and informal registers of the same language.

Application: Here, monolingual speakers move from a formal register to an informal one while continuing to express the same spoken or gestured idea. Because only the register changes and the language itself stays constant, this is a within-language style shift — the defining case of code-switching.

Contrast with the other terms offered:

• Code-mixing: names the blending of vocabulary, grammar, or phrases from two or more distinct languages inside a single utterance; it requires more than one language in play, which does not fit a monolingual speaker.

• Dialects: names a category of language varieties tied to region or social group; it labels a type of variety, not the act of moving between registers.

• Sociolinguistics: names the academic field that studies language in its social context; it is a discipline, not a behaviour a speaker performs.

Because the scenario is a monolingual register shift rather than a mixing of languages, a labelled variety, or a field of study, the described behaviour is code-switching. This matches the official CTET August 2023 Paper II answer key.