Discourse is generally any form of verbal communication, whether spoken or written. The role of discourse in linguistics is to provide a body of text for various types of analysis. These may include research into grammar, sociolinguistics, psycholinguistics and discourse analysis.
Corpus linguistics is the area where discourse is most commonly used in linguistics. The word corpus means "body," so a linguistic corpus is a body of text or speech occurring in the real world. Whereas much linguistic research can be done on texts created for the purpose of linguistic research, such as most research related to computer-generated language, corpus linguistics relies exclusively on naturally occurring language. Discourses of various types can provide language for this type of research, which may seek to analyze, for instance, levels of competence among language learners.
Researchers might use discourse in linguistics research relating to sociology and psychology. For example, sociolinguistic research indicates that on average, women use more pronouns than men. Pronoun usage can also be used as a predictor of a person's personality and emotional health. People who are emotionally healthy, for instance, tend to use plural pronouns like "we" or "their" much more often than they use singular pronouns like "I" or "me." These conclusions were reached by studying samples of discourse.
The French philosopher Michel Foucault used the term "discourse" to refer to the relationship of communication in real-world power structures. Foucault was more of a social theorist than a linguist; nevertheless, his theories about pragmatics, or how language coveys meaning, has had significant influence on the way many academicians view discourse. As Foucault uses the term, the role of discourse in linguistics is to establish the real-world meaning of statements. He argued that discourse locks people into certain modes of thought and action.
Following in Foucault's footsteps, various other disciplines have examined discourse in linguistics as well as other areas. Feminist theorists, for instance, may analyze the relationship between gender relations and the way people speak about gender. This type of analysis generally does not use the highly structured, scientific research methods used in mainstream linguistics, but may use the conclusions of linguistic research in their analyses of other texts, including literature.