christel kemke 2007/08 comp 4060 natural language processing discourse and dialogue
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Christel Kemke
COMP 4060 Natural Language Processing
Discourse and Dialogue
2007/08 Christel Kemke
Discourse and Dialogue
Discourse Phenomena Speech Acts Dialogue Acts
2007/08 Christel Kemke
Discourse
Discourse = collocated, related group of sentences
Monologues and Dialogues Referring Expressions: he, she Coherence Discourse Structure
see Jurafsky and Martin, Ch. 18 and 19
2007/08 Christel Kemke
Reference
Referring Expressions Referent
the Jurafsky
the 406 textbook
2007/08 Christel Kemke
Reference
Discourse Model - keeps track of representations of entities mentioned in discourse so far
Referring Expression - encodes information / signals for hearer to identify referent
Methods: Determine mapping from sign in referring expression to set
of beliefs / discourse model of hearer. Referents can be different parts, aspects of a sentence or
utterance. Use constraints on co-reference (syntax, discourse) to
determine mapping.
2007/08 Christel Kemke
Reference
"According to John, Bob bought Sue an Integra, and Sue bought Fred a Legend."
a) But that turned out to be a lie. speech actb) But that was false. propositionc) That caused Sue to become rather poor. eventd) That caused both of them to become rather
poor. combination of events
2007/08 Christel Kemke
Reference
Indefinite / definite noun phrases specific / non-specific entity
Pronouns salience (last mentioned) cataphora (pronoun mentioned before entity) bound in context of "quantified variable"
Demonstratives (this, that) "spatial proximity" (metaphorically), e.g. old - new
car
2007/08 Christel Kemke
Coherence
Coherence Relations (Hobbs) – model "connectedness" of sentences in text
ResultJohn bought an Acura. His father went ballistic.
ExplanationJohn hid Bill's car keys. He was drunk.
ParallelJohn bought an Acura. Bill leased a BMW.
ElaborationJohn bought an Acura this weekend. He purchased a new beautiful Acura for ... on Saturday afternoon.
OccasionJohn bought an Acura. He drove to the ballgame.
2007/08 Christel Kemke
Discourse Structure
Arrangement of sentence elements into (coherent) text / analysis of text according to coherence relations
Jurafsky and Martin, Figure 18.10, p. 705
Christel Kemke
Speech Acts
2007/08 Christel Kemke
Three Aspects of Speech Acts
Locutionary: the literal meaning of the utterance
Illocutionary: the social function that the utterance or written text has (e.g. informing, ordering, warning, undertaking.)
Perlocutionary: the result or effect that is produced by the utterance in that given context (e.g. convincing, persuading, deterring.)
2007/08 Christel Kemke
Illocutionary Acts
Assertives Directives Commissives Permissives Prohibitives Declaratives
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Speech Acts
Assertives committing the speaker to something's being the case “The door is shut.”
Directives attempts by the speaker to get the addressee to do something “Shut the door.”
Commissives committing the speaker to some future course of action “I will shut the door.”
Expressives expressing the psychological state of the speaker about a state
of affairs "Thanks for shutting the door."
2007/08 Christel Kemke
Speech Acts
Permissives allow / permit the hearer to a course of action as
described by the propositional content of the utterance "You may shut the door."
Prohibitives deny the hearer to a course of action as described by the
propositional content "Don't shut the door."
Declarations / Declaratives bringing about a different state of the world via the
utterance "You're fired."
2007/08 Christel Kemke
DAMSL - Dialogue Act Markup in Several Layers
Statement Info-request
Check Influence on Addressee Influence on Speaker
Offer Commit
Conventional Opening ...
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Questions and Frames
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Reference
Dan Jurafsky and James H. Martin, Speech and Language Processing, 1st Edition, Chapters 18 and 19, Prentice-Hall, 2000