Elements of Language
We distinguish several ways in which grammar is functional:
It has to express our interpretation of the world as we experience it (ideational/representational functional) and it helps us interact with others in order to bring changes to our environment (interpersonal function). In other words, grammar helps us organize our message in order to enable representation and interaction.
The regular patterns of different kinds reflect the uses which a language serves. For example, “declarative”, “interrogative”, “imperative” structural patterns (patterns of the Verb Group) help us to express a multitude of types of social behavior, whereas Nominal Group patterns enable us to encode information about entities: people, events, things, abstractions, etc. If we come to describe patterns involving syntactic categories (Subjects, Objects, Themes, etc) then we expand our analysis beyond the one-to-one relationship between them, to larger units: CONTEXT, CO-TEXT in the speaker-hearer relationship.
Each linguistic element is seen not in isolation but in relation to others, since it has potential to realize different functions. From a multitude of patterns speakers are free to chose those patterns which best convey the message at every stage of their interaction with other speakers.
A communicative/functional grammar is a new direction in grammar writing devoted to the uses of grammar, rather than to grammatical structure, employing a communicative rather than structural approach. The conceptual framework of this grammar is a functional rather than a formal one. It is functional in three closely related senses, in interpretation of texts, of systems and of elements of linguistic structures.
The conventional, traditional method of presenting English grammar in terms of structure, of its constitutive elements has a certain drawback in itself. It discuss elements in their individuality, underlining less the relations existing between them. Thus for example, in such grammar notions of time occur, or may be dealt with in four different places: the tense of the verb, time adverbs, prepositional phrases denoting time, temporal conjunctions and clauses. The student who is primarily interested in making use of the language will find it a boring and tedious job to look in detail at the theoretical aspects of grammar structures jumping from one place to another. The student will therefore benefit systematically related to meanings, uses and situations. (See G. Leech / J. Svartvik)
This “unconventional” type of grammar is designed to show how the language is used. Every text, said or written, unfolds in some context of use; furthermore, it is the uses of language that, in time, have shaped the system. Ever since it was intended, language has evolved to satisfy human needs and will continue to evolve along with humankind. Therefore, the way language is organized is functional with respect to these needs. From this point of view as M. A. K. Halliday puts it, a functional grammar is essentially a “natural” grammar, in the sense that everything in it can be explained by reference to how language is used.
Secondly, the fundamental components of meaning in language are functional components. According to Halliday, “all languages are organized around two main kinds of meaning: the “ideational” (or reflective) and the “interpersonal” (or active). These two components, also known as “metafunctions,” are [practically] manifestations in the linguistic system of the two very general purposes which underline all uses of the language: to understand the environment (ideational), and to act on the others in it (interpersonal).”