Editing Michael Halliday (section)

==Studies in child language development==
In enumerating his claims about the trajectory of children's language development, Halliday eschews the metaphor of "acquisition", in which language is considered a static product that the child takes on when sufficient exposure to natural language enables "parameter setting". By contrast, for Halliday what the child develops is a "meaning potential". Learning language is ''Learning how to mean'', the name of his well-known early study of a child's language development.<ref>Halliday, M.A.K. 1975. ''Learning How to Mean''. London: Edward Arnold.</ref>

Halliday (1975) identifies seven functions that language has for children in their early years. For Halliday, children are motivated to develop language because it serves certain purposes or functions for them. The first four functions help the child to satisfy physical, emotional, and social needs. Halliday calls them instrumental, regulatory, interactional, and personal functions.

* '''Instrumental''': This is when children use language to express their needs (e.g. "Want juice.")
* '''Regulatory''': This is where language is used to tell others what to do (e.g. "Go away.")
* '''Interactional''': Here language is used to make contact with others and form relationships (e.g. "Love you, Mummy.")
* '''Personal''': This is the use of language to express feelings, opinions, and individual identity (e.g. "Me good girl.")

The next three functions are heuristic, imaginative, and representational, all helping the child to come to terms with his or her environment.

* '''Heuristic''': This is when language is used to gain knowledge about the environment (e.g. "What is the tractor doing?")
* '''Imaginative''': Here language is used to tell stories and jokes and to create an imaginary environment.
* '''Representational''': The use of language to convey facts and information.

According to Halliday, as the child moves into the mother tongue, these functions give way to the generalised "metafunctions" of language. In this process, in between the two levels of the simple protolanguage system (the "expression" and "content" pairing of the Saussure's sign), an additional level of content is inserted. Instead of one level of content, there are now two: lexicogrammar and semantics. The "expression" plane also now consists of two levels: phonetics and phonology.<ref>Halliday, M.A.K. 2003. "On the 'architecture' of human language". In ''On Language and Linguistics''. Vol. 3 in ''The Collected Works''. London and New York: Equinox.</ref>

Halliday's work is sometimes seen as representing a competing viewpoint to the formalist approach of [[Noam Chomsky]]. Halliday's stated concern is with "naturally occurring language in actual contexts of use" in a large typological range of languages.  Critics of Chomsky often characterise his work, by contrast, as focused on English with Platonic idealisation, a characterisation that Chomskyans reject (see [[Universal Grammar]]).