Metafunction

The term metafunction originates in systemic functional linguistics and is considered to be a property of all languages. Systemic functional linguistics is functional and semantic rather than formal and syntactic in its orientation. As a functional linguistic theory, it claims that both the emergence of grammar and the particular forms that grammars take should be explained "in terms of the functions that language evolved to serve".^[1] While languages vary in how and what they do, and what humans do with them in the contexts of human cultural practice, all languages are considered to be shaped and organised in relation to three functions, or metafunctions. Michael Halliday, the founder of systemic functional linguistics, calls these three functions the ideational, interpersonal, and textual. The ideational function is further divided into the experiential and logical.

Metafunctions are systemic clusters; that is, they are groups of semantic systems that make meanings of a related kind. The three metafunctions are mapped onto the structure of the clause. For this reason, systemic linguists analyse a clause from three perspectives. Halliday argues that the concept of metafunction is one of a small set of principles that are necessary to explain how language works; this concept of function in language is necessary to explain the organisation of the semantic system of language.^[2] Function is considered to be "a fundamental property of language itself".^[3]

According to Ruqaiya Hasan, the metafunctions in SFL "are not hierarchised; they have equal status, and each is manifested in every act of language use: in fact, an important task for grammatics is to describe how the three metafunctions are woven together into the same linguistic unit".^[4] Hasan argues that this is one way in which Halliday's account of the functions of language is different from that of Karl Bühler, for example, for whom functions of language are hierarchically ordered, with the referential function the most important of all. For Buhler, the functions were considered to operate one at a time. In SFL, the metafunctions operate simultaneously, and any utterance is a harmony of choices across all three functions.^[5]