Final answer:
Formal language is used in academic or professional settings, while informal language is appropriate in casual conversations or personal narratives.
Step-by-step explanation:
Formal language is typically used in academic or professional settings, such as writing essays, giving presentations, or communicating with superiors. It is characterized by proper grammar, complex sentence structures, and a professional tone. On the other hand, informal language is appropriate in casual conversations, texts or emails to friends, or when writing personal narratives. It is more relaxed, uses slang or colloquial expressions, and may include abbreviations or emojis.