Discourse community  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:  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." Porter held the belief that all new ideas added to a discourse community had an impact on the group, changing it forever. 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."