Michael Halliday

His book An Introduction to Functional Grammar, first published in 1985. A revised edition was published in 1994, and then a third, in which he collaborated with Christian Matthiessen, in 2004. The fourth edition was published in 2014.

Systemic functional grammar (SFG)

Systemic-Functional Linguistics (SFL) is a theory of language centred around the notion of language function. While SFL accounts for the syntactic structure of language, it places the function of language as central (what language does, and how it does it), in preference to more structural approaches, which place the elements of language and their combinations as central. SFL starts at social context, and looks at how language both acts upon, and is constrained by, this social context. SFL is the use of system networks, an inheritance network used to represent the choices present in making an utterance. The choices in this network are called features. The choices on each stratum are constrained by those on others. Thus the decision to use a nominal-group (= noun-phrase), rather than a clause, to express a semantic ‘process’ will be determined by both the textual structure of the text as a whole, and also by the social context. Each feature is also associated with the structural consequences of that choice, e.g., the feature ‘finite’ might have realization: +Subject; +Finite; Subject: [nominal-group]; Finite: [finite-verb], meaning a Subject and Finite element are required, the Subject is filled by a nominal group, and the Finite by a finite-verb. Further selections in the clause network will more tightly constrain the fillers of these roles, and specify the presence, fillers, and ordering of these elements.

Michael Halliday has contributed significantly to theories of language and related areas. Best known for developing systemic functional linguistics (SFL), he transformed views about language by making choice a core concept of his theory, where choice in the language system is between meanings rather structures. He has worked in various regions of language study, both theoretical and applied, and has been especially concerned with applying the understanding of the basic principles of language to the theory and practices of education.