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As discourse, an "enouncement" (statement) is not a unit of semiotic signs, but an abstract construct that allows the semiotic signs to assign meaning, and so communicate specific, repeatable communications to, between, and among objects, subjects, and statements. Therefore, a discourse is composed of semiotic sequences (relations among signs that communicate meaning) between and among objects, subjects, and statements.
The term "discursive formation" (French: formation discursive) conceptually describes the regular communications (written and spoken) that produce such discourses, such as informal conversations. As a philosopher, Michel Foucault applied the discursive formation in the analyses of large bodies of knowledge, such as political economy and natural history.
In the first sense-usage (semantics and discourse analysis), the term discourse is studied in corpus linguistics, the study of language expressed in corpora (samples) of "real world" text. In the second sense (the codified language of a field of enquiry) and in the third sense (a statement, un énoncé), the analysis of a discourse examines and determines the connections among language and structure and agency.
Moreover, because a discourse is a body of text meant to communicate specific data, information, and knowledge, there exist internal relations in the content of a given discourse; likewise, there exist external relations among discourses. As such, a discourse does not exist per se (in itself), but is related to other discourses, by way of inter-discursivity. Discourses are also perpetually differentiating toward each other in time. Therefore, in the course of intellectual enquiry, the discourse among researchers features the questions and answers of What is ...? and What is not. ..., conducted according to the meanings (denotation and connotation) of the concepts (statements) used in the given field of enquiry, such as anthropology, ethnography, and sociology; cultural studies and literary theory; the philosophy of science and feminism.
In sociology, discourse is defined as "any practice (found in a wide range of forms) by which individuals imbue reality with meaning". In the humanities and in the social sciences it describes a formal way of thinking that can be expressed through language; the discourse is a social boundary that defines what statements can be said about a topic. Some definitions of discourse are largely derived from the work of French philosopher Michel Foucault.
Discourse is closely linked to politics and policy making as well as to different theories of power and state, at least as long as defining discourses is seen to mean defining reality itself.
Discourse can affect the person's perspective; it is impossible to avoid discourse for any subject. For example, two notably distinct discourses can be used about various guerrilla movements describing them either as "freedom fighters" or "terrorists". In other words, the chosen discourse provides the vocabulary, expressions and perhaps also the style needed to communicate.
Discourses are embedded in different rhetorical genres and metagenres that constrain and enable them--language talking about language, exemplified in how the American Psychiatric Association's DSMIV manual tells which terms have to be used in talking about mental health, thereby mediating meanings and dictating practices of the professionals of psychology and psychiatry.
Modern theorists were focused on achieving progress and believed in the existence of natural and social laws which could be used universally to develop knowledge and thus a better understanding of society. Modernist theorists were preoccupied with obtaining the truth and reality and sought to develop theories which contained certainty and predictability. Modernist theorists therefore viewed discourse as being relative to talking or way of talking and understood discourse to be functional. Discourse and language transformations are ascribed to progress or the need to develop new or more "accurate" words to describe new discoveries, understandings, or areas of interest. In modern times, language and discourse are dissociated from power and ideology and instead conceptualized as "natural" products of common sense usage or progress.Modernism further gave rise to the liberal discourses of rights, equality, freedom, and justice; however, this rhetoric masked substantive inequality and failed to account for differences, according to Regnier.
Structuralist theorists, such as Ferdinand de Saussure and Jacques Lacan, argue that all human actions and social formations are related to language and can be understood as systems of related elements. This means that the "...individual elements of a system only have significance when considered in relation to the structure as a whole, and that structures are to be understood as self-contained, self-regulated, and self-transforming entities."  In other words, it is the structure itself that determines the significance, meaning and function of the individual elements of a system. Structuralism has made an important contribution to our understanding of language and social systems.Saussure's theory of language highlights the decisive role of meaning and signification in structuring human life more generally.
Following the perceived limitations of the modern era, emerged postmodern theory. Postmodern theorists rejected modernist claims that there was one theoretical approach that explained all aspects of society. Rather, postmodernist theorists were interested in examining the variety of experience of individuals and groups and emphasized differences over similarities and common experiences.
In contrast to modern theory, postmodern theory is more fluid and allows for individual differences as it rejected the notion of social laws. Postmodern theorists shifted away from truth seeking and instead sought answers for how truths are produced and sustained. Postmodernists contended that truth and knowledge is plural, contextual, and historically produced through discourses. Postmodern researchers therefore embarked on analyzing discourses such as texts, language, policies and practices.
French social theorist Michel Foucault developed a notion of discourse in his early work, especially the Archaeology of knowledge (1972). In Discursive Struggles Within Social Welfare: Restaging Teen Motherhood, Iara Lessa summarizes Foucault's definition of discourse as "systems of thoughts composed of ideas, attitudes, courses of action, beliefs and practices that systematically construct the subjects and the worlds of which they speak." Foucault traces the role of discourses in wider social processes of legitimating and power, emphasizing the construction of current truths, how they are maintained and what power relations they carry with them. Foucault later theorized that discourse is a medium through which power relations produce speaking subjects.
Foucault (1977, 1980) argued that power and knowledge are inter-related and therefore every human relationship is a struggle and negotiation of power. Foucault further stated that power is always present and can both produce and constrain the truth. Discourse according to Foucault (1977, 1980, 2003) is related to power as it operates by rules of exclusion. Discourse therefore is controlled by objects, what can be spoken of; ritual, where and how one may speak; and the privileged, who may speak. Coining the phrases power-knowledge Foucault (1980) stated knowledge was both the creator of power and creation of power. An object becomes a "node within a network." In his work, The Archaeology of Knowledge, Foucault uses the example of a book to illustrate a node within a network. A book is not made up of individual words on a page, each of which has meaning, but rather "is caught up in a system of references to other books, other texts, other sentences." The meaning of that book is connected to a larger, overarching web of knowledge and ideas to which it relates.
One of the key discourses that Foucault identified as part of his critique of power-knowledge was that of neoliberalism, which he related very closely to his conceptualization of governmentality in his lectures on biopolitics. This trajectory of Foucault's thinking has been taken up widely within Human Geography.