Discourse Analysis

Radhika Mamidi

Coherence and cohesion

• What makes a text coherent?• What are the coherent devices?

Discourses have to have connectivity to be coherent.

Eg. Ram took up a job. Shyam went to university.

Insert because/and/so/but between the sentences and see the connectivity.

Example: Incoherent text

The sky was clear and the day was bright. The cat was asleep. The roses are red and the grass is green. Tom and Jerry are at it again.

Building background…

I got up early today. As usual, I switched on the TV and then pulled the curtains. The sky was clear and the day was bright. I looked at my garden. The cat was asleep. I sang to myself: The roses are red and the grass is green…. My eyes shifted to my TV and I sighed - Tom and Jerry are at it again.

Activity: What are the inferences you drew?

Context dependent situations

• Referring expressions: pronouns, definite expressions etc.

• Universe of discourse: Every student was absent today.

• Responses to questions: Who is absent? Ravi.• Implicit relationship between events:

Max fell. John pushed him.

Factors influencing discourse interpretation

• Cue phrases – and, but, because, so• Punctuation

Max fell (John pushed him) and Kim laughed.Max fell, John pushed him and Kim laughed.

• Real world contentJohn poisoned Bill. He died within a week.John poisoned Bill. He was arrested within a week.

• Tense and aspectMax fell. John had pushed him.Max was falling. John pushed him.

Relation between sentences

• Rhetorical structure theory (Mann and Thomson, 1987)

• Discourse relations (Hobbs, 1979)

Discourse relations

Example (from Asher and Vieu, 2004)a. John had a great evening last night.b. He had a great meal.c. He ate salmon.d. He devoured lots of cheese.e. He then won a dancing competition.f. ? Then he had a great dessert.f’. # It was a beautiful pink.f’’. John had lots of fun.

Types of discourse relations

• Result: John failed. His mother became angry.• Explanation: John failed. He did not study

hard.• Parallel: John failed. Bill topped the class.• Elaboration: John failed. He felt miserable.• Occasion: John failed. He went to the bar.

Rhetorical Structure Theory

• Originally formulated by Mann and Thompson 1988• A unified view of discourse structure, irrespective of the

size of discourse segments• A nomenclature of rhetorical relations between

discourse segments• Each discourse segment serves the realization of the

overall communicative intention of the speaker• A descriptive theory of text organisation based on the

relationships that hold between parts of the texts.• Central segment – nucleus• Peripheral segment - satellite

Rhetorical relations

• Elaboration: I work at IIIT. IIIT is a deemed university.

• Contrast: I love tea. But I will have coffee.• Condition: I will have coffee. If you will make it.• Purpose: I made a cake. It is my friend’s

birthday.• Sequence: I made a cake. Then I did the icing.• Result: The cake was nice. It made my friend

happy.

Discourse structures

Speech Acts

Searle (1975): (modification of Austin)• Assertives: suggesting, boasting, concluding• Directives: asking, ordering, inviting• Commissives: promising, planning, vowing• Expressives: thanking, apologising• Declarations: Using performative verbs

Dialogue Acts

• Speech acts involve pragmatic force• Dialogues acts: Speech acts + more kinds of conversational

functions• DAMSL - Dialog Act Markup in Several Layers - `defines a

set of primitive communicative actions that can be used to analyze dialogs'.

• It codes various levels of dialogue information about utterances.

• Two of these levels, forward and backward looking functions are extensions of speech acts drawing on notions like adjacency pairs, grounding and repair.

Forward looking function

Backward looking function