The term metafunction originates in systemic functional linguistics and is considered to be a property of all languages.
Thus, the human species had to "make sense of the complex world in which it evolved: to classify, or group into categories, the objects and events within its awareness".
[7] In taking this position on the active role of grammar in construing "reality", Halliday was influenced by Whorf.
[10] Halliday argues that these encounters: The grammatical systems that relate to the interpersonal function include Mood, Modality, and Polarity.
These systems "create coherent text – text that coheres within itself and with the context of situation" [8] They are both structural (involving choices relating to the ordering of elements in the clause), and non-structural (involving choices that create cohesive ties between units that have no structural bond).
[13] Halliday argues that the textual function is distinct from both the experiential and interpersonal because its object is language itself.
Through the textual function, language "creates a semiotic world of its own: a parallel universe, or 'virtual reality' in modern terms".