||This article may be weighted too heavily toward only one aspect of its subject. (March 2011)|
A discourse community is a group of people who share a set of discourses, understood as basic values and assumptions, and ways of communicating about those goals. Linguist John Swales defined discourse communities as "groups that have goals or purposes, and use communication to achieve these goals."
Some examples of a discourse community might be those who read and/or contribute to a particular academic journal, or members of an email list for Madonna fans. Each discourse community has its own unwritten rules about what can be said and how it can be said: for instance, the journal will not accept an article with the claim that “Discourse is the coolest concept”; on the other hand, members of the email list may or may not appreciate a Freudian analysis of Madonna’s latest single. Most people move within and between different discourse communities every day.
Since the discourse community itself is intangible, it is easier to imagine discourse communities in terms of the fora in which they operate. The hypothetical journal and email list can each be seen as an example of a forum, or a "concrete, local manifestation of the operation of the discourse community".
The term was first used by sociolinguist Martin Nystrand in 1982, and further developed by American linguist John Swales. Writing about the acquisition of academic writing styles of those who are learning English as an additional language, Swales presents six defining characteristics:
- A discourse community:
- has a broadly agreed set of common public goals.
- has mechanisms of intercommunication among its members.
- uses its participatory mechanisms primarily to provide information and feedback.
- utilizes and hence possesses one or more genres in the communicative furtherance of its aims.
- in addition to owning genres, it has acquired some specific lexis.
- has a threshold level of members with a suitable degree of relevant content and discoursal expertise.
James Porter defined the discourse community as: “a local and temporary constraining system, defined by a body of texts (or more generally, practices) that are unified by a common focus. A discourse community is a textual system with stated and unstated conventions, a vital history, mechanisms for wielding power, institutional hierarchies, vested interests, and so on.” 
Argumentation theorists Chaim Perelman and Lucie Olbrechts-Tyceta offer the following statement on the conditioned nature of all discourse, which has applicability to the concept of discourse community: "All language is the language of community, be this a community bound by biological ties, or by the practice of a common discipline or technique. The terms used, their meaning, their definition, can only be understood in the context of the habits, ways of thought, methods, external circumstances, and tradition known to the users of those terms. A deviation from usage requires justification ..." 
"Producing text within a discourse community," according to Patricia Bizzell, "cannot take place unless the writer can define her goals in terms of the community's interpretive conventions." In other words, one cannot simply produce any text — it must fit the standards of the discourse community to which it is appealing. If one wants to become a member of a certain discourse community, it requires more than learning the lingo. It requires understanding concepts and expectations set up within that community.
The language used by discourse communities can be described as a register or diatype, and members generally join a discourse community through training or personal persuasion. This is in contrast to the speech community (or the 'native discourse community', to use Bizzell's term), who speak a language or dialect inherited by birth or adoption.
Discourse communities are studied in the larger field of genre analysis. Related terms include Miller's "rhetorical community" and, focusing on the communication rather than the community, Yates & Orlikowski's "genres of organizational communication" 
James Paul Gee uses discourse as a way of “(writing)-doing-being-valuing-believing combinations” (Gee 142). Discourse can be connected to the concept of audience in that both the audience and the writer partake in a series of historical contingencies that place the writer and audience into a larger conversation with one another. It is an “identity kit” of sorts: "A Discourse is a sort of ‘identity kit’ which comes complete with the appropriate costume and instructions on how to act, talk, and often write, so as to take on a particular social role that others will recognize. Imagine what an identity kit to play the role of Sherlock Holmes would involve: certain clothes, certain ways of using language (oral language and print), certain attitudes and beliefs, allegiance to a certain life style, and certain ways of interacting with others. We can call all these factors together, as they are integrated around the identity of ‘Sherlock Holmes, Master Detective’ the ‘Sherlock Holmes Discourse’. This example also makes clear that ‘Discourse’, as I am using the term, does not involve just talk or just language. (Gee 142) Furthermore, discourses are not individualistic, but rather community-based, in official (institutional frameworks) capacities, unofficial (social groups) capacities, or both. Specifically, “Discourses are always embedded in a medley of social institutions, and often involve various ‘props’ like books and magazines of various sorts, laboratories, classrooms, buildings of various sorts, various technologies, and a myriad of other objects from sewing needles (for sewing circles) through birds (for bird watchers) to basketball courts and basketballs (for basketball players)” (143).
- Borg, Erik. Discourse communities (ELT Journal 57:4)
- Porter, J. (1992). Audience and Rhetoric: An Archaeological Composition of the Discourse Community. New Jersey: Prentice Hall.
- Nystrand, M. (1982) What Writers Know: The Language, Process, and Structure of Written Discourse. New York: Academic
- Swales, J. M. (1990) Genre Analysis: English in academic and research settings. Cambridge: Cambridge University Press.
- Perelman, Chaim and Lucie Olbrechts-Tyceta (1969) The New Rhetoric: A Treatise on Argumentation. Trans. John Wilkinson and Purcell Weaver.
- Bizzell, P. (1992) Academic Discourse and Critical Consciousness. Pittsburgh: University of Pittsburgh Press.
- Miller, Carolyn R. "Rhetorical community: The cultural basis of genre." Genre and the new rhetoric (1994): 67-78.
- JoAnne Yates and Wanda J. Orlikowski. "Genres of organizational communication: A structurational approach to studying communication and media." Academy of Management Review 17.2 (1992): 299-326.