What type of language is referred to as casual language used in conversation with friends?

Colloquial language is the correct answer as it represents informal language that is commonly used in everyday conversation among friends and peers. This type of language often includes slang, idiomatic expressions, and casual phrasing, making it relatable and easy to understand in a social context. Colloquialisms are typically region-specific and can vary significantly from one area to another, reflecting the cultural and social nuances of the speakers.

In contrast, formal language is characterized by a more structured and serious tone, commonly used in professional settings, academic writing, or official communications. Casual language, while it might seem like a fitting term, is not an established linguistic category and could be confused with colloquial language, which is more specifically recognized. Intimate language refers to the personal and affectionate language used between close relationships, which may not encompass the broader, casual speech used among friends. Therefore, colloquial language best captures the essence of informal, conversational exchanges among peers.