The distinction between text and discourse is not clear-cut and there have been many other uses of these labels. In particular, both ‘discourse' and ‘text' can be used in a much broader sense to include all language units with a definable communicative function, whether spoken or written.
Some scholars talk about ‘spoken and written discourse' others about ‘spoken and written text'. In Europe, the term text linguistics is often used for the study of the linguistic principles governing the structure of all forms of texts.
The search for larger linguistic units and structures has been pursued by scholars from many disciplines. Linguists investigate the features of language that bind sentences when they are used in sequence. Ethnographers and sociologists study the structure of social interaction, especially as manifested in the way people enter into dialogue. Anthologists analyse the structure of myths and folk-tales. Psychologists carry out experiment on the mental process underlying comprehension and further contribution have come from those concerned with artificial intelligence, rhetoric, philosophy, and style.
These approaches have a common concern: they stress the need to see language as a dynamic, social interactive phenomenon whether between speaker and listener, or writer and reader. It is argued that meaning is conveyed not by single sentences but by more complex exchanges, in which the participants' beliefs and expectations, the knowledge they share about each other and about the world, and the situation in which they interact, play a crucial part.