1 / 16

Discourse Markers

Discourse Markers. Discourse & Dialogue CS 35900 November 25, 2006. Agenda. Definition Motivation Understanding Discourse Markers in Human-Human Dialogue Using Discourse Markers in HCI Structuring instructions Improving recognition Recognizing conversational and dialogue acts.

ssteven
Download Presentation

Discourse Markers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Discourse Markers Discourse & Dialogue CS 35900 November 25, 2006

  2. Agenda • Definition • Motivation • Understanding Discourse Markers in Human-Human Dialogue • Using Discourse Markers in HCI • Structuring instructions • Improving recognition • Recognizing conversational and dialogue acts

  3. Discourse Markers • “Cue”/”Clue” phrases • E.g.“By the way”, “so”, “now”, “anyway” • Signal discourse structure • E.g. asides, new topics, returns • Signal relations between segments • Cohesion, continuation, contrast, etc • Appropriate use clarifies dialogue • Misuse causes confusion

  4. Lost in the Mail (Application) • U: Read old messages. • S:Skipping to first old message. Message 1 from Shaw Wen Yang, Subject: Question • U: Read it to me. • S: Call me about the tool, shaw x22630 • U:Send a reply. • S:Preparing message to shaw. Do you want to include the current message? • U: Yes • S:Begin recording after the tone……Say cancel, send or review. • U: Send • S: Message sent. • U: <silence>….<touch tones>...

  5. Why Discourse Markers? • Prevalent: • Begin 65% human-human task utterances • 44% excluding acknowledgments • Related to discourse meaning/structure • How do linguistic features of DMs interact with discourse properties to create function? • What is the scope? • At what level is relationship marked? • How do meanings contribute to function?

  6. Discourse Relations • Markers apply on different planes of talk • exchange, action, idea, participation framework, information status • E.g. ‘oh’: primary: info state; 2nd: action, participation • Semantics and syntax contribute to role of DM • E.g. “so” -> result • Mark or disambiguate relations • Don’t create relations

  7. Levels of Contribution • Wide scope -> less communicative force • Narrow scope -> more communicative force • More markers -> decrease individual impact • Clearer discourse structure -> fewer DMs

  8. Indexical Relations • Utterance situated with respect to • Speaker, hearer, time, place • Discourse markers related to context • Proximal (near) vs distal (far) relations • Linkage to preceding/following utterance • preceding - “oh” - proximal; “well”: link pre & post • Speaker - proximal =“oh”; hearer- distal

  9. Discourse Markers & Coherence • Establish coherence by • Locate utterance on “plane of talk” • Exchange, action, idea, participation frame, info status, etc • Turn-taking, task step, semantics, attitude, etc • Index local context reference for interpretation • Establish direction of relation to surrounding utts

  10. A Solution • U: Read old messages. • S:Skipping to first old message. Message 1 from Shaw Wen Yang, Subject: Question • U: Read it to me. • S: Call me about the tool, shaw x22630 • U:Send a reply. • S:Preparing message to shaw. Do you want to include the current message? • U: Yes • S:Begin recording after the tone……Say cancel, send or review. • U: Send • S: Message sent. What now? • U: Next message.

  11. Generating Discourse Markers • Integrate intentional & informational • Grosz & Sidner; Mann & Thompson • Identify nuclear DSP and contributing relations • Pairwise relations of rhetorical types (intent) • E.g. concession:nucleus • Relations based on task/domain (inform) • E.g. step:prev-result • Interpret cues wrt discourse structure/relations • “since”: contributor:nucleus;”because”:nucleus:contributor • No duplication of cues within embedded relations • Duplicate in sequence

  12. Characterizing Discourse Markers • Problem: Ambiguity • Discourse use vs sentential use • E.g. “now”: Topic initiation vs temporal meaning • Overall: 1/3 ambiguous; coord conj: ½ • Disambiguation: • Prosody: 84% (non-conj: 93%) • DM: own intermediate phrase; or first, no accent • Sentence: no separation, H* or complex accent • Text: 89% • DM: preceding punctuation • POS weaker cue

  13. Improving Recognition • Discourse markers as special case of POS tagging • POS = part of speech • E.g. noun, verb, conjunction, etc • Discourse marker POS: • Acknowledgment: “okay”; “uh-huh” • Interjection DM: “oh”,”well” • Conjunction DM: “and”,”but” • Adverb DM: “now”,”then”

  14. Recognizing Markers • Build joint model of word+POS recognition • Expand ASR model • Build decision trees to identify equivalences • Handle sparseness • Build binary classification trees • Successive merging with least information loss • Apply to POS and word+POS pairs • Cluster unambiguously • Joint modeling improves POS tagging • Additional discourse features further improve • Boundary tones, repairs, silence

  15. Discourse Markers & Structure • Discourse markers correlated with conversational moves • E.g. “so”- summarize; “well” - dissent • Discourse markers NOT correlated with subsequent speech acts • Correlated with PRIOR talk • Previous turn initiates adjacency pair -> no DM • Previous turn concludes adjacency pair -> DM • Clear expectation: no DM; unclear -> DM

  16. Discourse Markers • Short cue word, phrases that signal • relation of utterance to its context • locate utterance in the “plane” of talk • Important role in disambiguating meanings • Signal shift in topic • Signal changes in footing • Key in loosely organized contexts

More Related