Systemic Functional Grammar (SFG) is a linguistic theory developed by Michael Halliday that focuses on how language functions in social contexts. It emphasizes the relationship between language and its use in communication, highlighting how choices in language reflect social meanings and purposes. SFG categorizes language into three main metafunctions: the ideational metafunction, which conveys ideas and experiences; the interpersonal metafunction, which expresses social relationships and attitudes; and the textual metafunction, which organizes information in a coherent manner. This framework helps analyze how language operates in various contexts and serves different communicative goals.