The following table abstracts the starting points, research questions, and minimal units for the six (6) major approaches to discourse analysis.
 

Structural	Starting Point	Research Question	Minimal Unit
Conversation Analysis	Sequencing/Adjacency	Why that next?	Adjacency Pair
Variationist Analysis	Structural Variable	Why that form?	Multiple Possibilities
Functional	------------------	------------------	------------------
Speech Act	Speaker Intention	How to do things with words?	Speech Act
Ethnography of Communication	Speech Events/Speech Acts	How does discourse reflect culture?	Speech Event
Interactional Sociolinguistics	Interpersonal Goals	What are they doing?	Interchange
Pragmatics	Grice's Maxims/ Speech Acts	What are the cultural norms for speech acts?	Multiple Possibilities

Adapted from Deborah Shiffrin, Approaches to Discourse, 1994.