Critical Discourse Analysis (CDA) is a field of study that draws on techniques used in Stylistics. Studies in CDA seek to understand how and why texts affect hearers/readers in particular ways. While Stylistics uses tools such as modality and transitivity to look at how fiction writers create certain textual effects, CDA uses these and other tools to look at non-fiction texts and the way they affect hearers/readers. These texts have been drawn from many different contexts: whilst studies often focus on political texts, researchers have also used the in-depth analysis of CDA to analyse advertising, television programmes and even swimming pool regulations.
CDA was developed at the University of East Anglia during the 1970s, by a team of linguists led by Roger Fowler. It was developed with the understanding that language plays a crucial role in shaping how we experience the world around us. Consciously or not, text producers take advantage of this in order to shape the hearer/reader's perception of the world. For example, in the build-up to a military invasion into a foreign country, a nation's political leaders might focus their talk on the threat posed by the foreign country, and to paint them in a particular (negative) light. This might be done explicitly ('Iraq poses a serious threat to our nation'), or in more subtle ways that play on the audience's fears. For example, certain modal terms might be used to suggest the possibility of certain dangers which may or may not be all that severe ('Iraq may have weapons of mass destruction, 'If we don't take action, democratic values might well be destroyed'). CDA uses tools such as modality to uncover these more subtle, implicit ideologies, focusing in particular on the language used by powerful institutions.
Many of the tools used in CDA are outlined elsewhere in the Linguistic Toolbox. Traditionally, tools based on frameworks such as modality, transitivity and nominalisation have been used. However, there is no set checklist of tools which should be applied to texts; instead, studies focus on whichever tools best suit their purposes. Further tools — such as naming, opposition and negation — have also been added as researchers have realised the potential ideological effects of various aspects of language. Many researchers have also made use of Corpus Linguistics in their work, helping to give a more 'scientific' basis to CDA studies.
For summaries of many of the tools traditionally used in CDA, and introductions to new tools, see:
Jeffries, L. (2010) Critical Stylistics: The Power of English Hampshire: Palgrave Macmillan
CDA tools are carefully explained in Richardson's study of British newspapers. The section on 'Critical Discourse Analysis' offers a good introduction to the field:
Richardson, J. E. (2007) Analysing Newspapers: An Approach from Critical Discourse Analysis Hampshire: Palgrave Macmillan, 26-45
The following textbook by Simpson and Mayr is designed for undergraduates, and demonstrates the usefulness of CDA tools through analysis of many different kinds of texts:
Simpson, P. and Mayr, A. (2010) Language and Power: A Resource Book for Students London: Routledge