The focus of discourse analysis is any form of written or spoken language, such as a conversation or a newspaper article. The main topic of interest is the underlying social structures, which may be assumed or played out within the conversation or text. It concerns the sorts of tools and strategies people use when engaged in communication, such as slowing one's speech for emphasis, use of metaphors, choice of particular words to display affect, and so on.

The investigator attempts to identify categories, themes, ideas, views, roles, and so on, within the text itself. The aim is to identify commonly shared discursive resources (shared apetterns of talking). The investigator tries to answer questins such as how the discourse helps us understand the issue under study, how people construct their own version of an event, and how people use discourse to maintain or construct their own identity.

In terms of conversational data, the researcher uses the transcript of the conversation (a systematic way of coding the words) as their source. An example might be mother-child conversations focussing on situations that provoke anxiety, or another might be a conversation among a group of factory workers about the royal family.

http://eamonfulcher.com/discourse_analysis.html