Systemic functional linguistics
Systemic functional linguistics (SFL) is an approach to language developed mainly by Michael Halliday in the U.K. during the 1960s, and later in Australia. The approach is now used world-wide, particularly in language education, and for purposes of discourse analysis.
While many of the linguistic theories in the world today are concerned with language as a mental process, SFL is more closely aligned with Sociology: it explores how language is used in social contexts to achieve particular goals. In terms of data, it does not address how language is processed or represented within the human brain, but rather looks at the discourses we produce (whether spoken or written), and the contexts of the production of these texts.
Because it is concerned with language use, SFL places higher importance on language function (what it is used for) than on language structure (how it is composed).
O’Donnell, Mick (2011) Introduction to Systemic Functional Linguistics for Discourse Analysis [web document] URL: http://web.uam.es/departamentos/filoyletras/filoinglesa/Courses/LFC11/LFC-2011-Week1.pdf Accessed 25/03/2016