In the context of language development, code-switching is a speech act in which:

• A. A child invents entirely new words to replace existing vocabulary
• B. A listener interprets ambiguous words based on context
• C. A speaker corrects their own grammatical errors while speaking
• D. A speaker alternates between two or more languages or language varieties within a conversation or utterance

Answer: (D)

Verified step by step guidance

1. Understand the concept of code-switching in language development, which involves the use of multiple languages or language varieties by a speaker.
2. Recognize that code-switching is not about inventing new words, interpreting ambiguous words, or self-correcting grammar, but rather about alternating between languages.
3. Identify examples of code-switching, such as a bilingual speaker switching from English to Spanish within a single conversation or sentence.
4. Note that code-switching reflects a speaker's ability to navigate and use different linguistic systems fluidly depending on context and audience.
5. Conclude that the correct definition of code-switching is when a speaker alternates between two or more languages or language varieties within a conversation or utterance.