The Effect of Contour Type and Epistemic Modality on the Assessment of Speaker Certainty Agustín Gravano1 · Stefan Benus2 · Julia Hirschberg1 Elisa Sneed German3 · Gregory Ward3 1 Columbia University 2 Univerzity Konštantína Filozofa 3 Northwestern University

Agustín Gravano Speech Prosody 2008 Overview Previous researchers disagree about the role of epistemic would in utterance interpretation. A: Who’s the British woman over there? B: That would be J. K. Rowling. Epistemic would conveys... Tentativeness (Palmer 1990, Perkins 1983) A high degree of speaker certainty (Ward et al. 2003) Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 Overview What is the relation between epistemic would and perceived speaker certainty? What role does the intonational contour play? Two perception experiments Textual condition Spoken condition Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 Epistemic modality Marks the speaker’s estimation of the likelihood that a certain proposition is true in context. A: Who’s the British woman over there? B: That must be J. K. Rowling. That could be J. K. Rowling. That might be J. K. Rowling. How is the perception of speaker certainty affected by the use of epistemic would? That would be J. K. Rowling. Agustín Gravano Speech Prosody 2008

Perception Study 1: Textual Condition Task Overview Participants were: 1) Presented with written dialogues. 2) Asked to assess the speaker certainty of a target utterance. Agustín Gravano Speech Prosody 2008

Perception Study 1: Textual Condition Materials [Context: David is at his desk when a co-worker knocks on the door.] Co-worker: David, I'm looking for this guy named Frank Jackson. David: That’s the new guy. or That would be the new guy. Agustín Gravano Speech Prosody 2008

Perception Study 1: Textual Condition Experiment Design Each session contained 60 tokens: 20 stimuli (only one stimulus from each set) 40 fillers without any of the target constructions Presented in a random order. Participants rated the perceived certainty of each token on a 5-degree Likert scale: Very uncertain, Somewhat uncertain, Neither certain nor uncertain, Somewhat certain, Very certain. Agustín Gravano Speech Prosody 2008

Perception Study 1: Textual Condition Computer Interface Agustín Gravano Speech Prosody 2008

Perception Study 1: Textual Condition Collected Data 12 participants (8 female, 4 male, mean age: 20.3) 240 data points (120 would be, 120 is) Participants’ responses were: 1) Converted into numeric values: Very uncertain  2 Somewhat uncertain  1 Neither certain nor uncertain  0 Somewhat certain  1 Very certain  2 2) Normalized using z-scores. Agustín Gravano Speech Prosody 2008

Perception Study 1: Textual Condition Results Mean certainty of would be tokens: 0.13 ± 1.11 is tokens: 0.03 ± 1.04 One-way ANOVA: No significant difference. No evidence of a difference in perceived certainty between modal would and indicative be, in a textual condition. Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 What is the case in a spoken condition? How is the perception of speaker certainty affected by: the use of epistemic would? the use of a particular intonational contour? Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Task Overview Participants were: 1) Presented with written dialogues and a recorded target utterance. 2) Asked to assess the speaker certainty of each target utterance. Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Computer Interface Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Intonational Contours Simple declarative contour (H*) H* L- L% Downstepped contour H* !H* (!H*) L- L% Yes-no-question contour (L*) L* H- H% Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Materials 20 stimulus sets, each with six variations of the same utterance (= 120 files): Recorded by a non-professional male speaker of American English in a sound-proof booth. declarative downstepped yn-question would be is Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Experiment Design Each session contained 60 tokens: 20 stimuli (only one stimulus from each set) 40 fillers (with all 3 contours: 13 dec, 13 ds, 14 yn) Presented in a random order. Participants rated the perceived certainty of each token on the same 5-degree Likert scale: Very uncertain, Somewhat uncertain, Neither certain nor uncertain, Somewhat certain, Very certain. Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Collected Data 30 participants (24 female, 6 male, mean age: 21.4) 600 data points: Again, participants’ responses were: 1) Converted into numeric values. 2) Normalized using z-scores. declarative downstepped yn-question would be 100 is Agustín Gravano Speech Prosody 2008

Perception Study 2: Spoken Condition Results No interaction between Contour and Modality. For all 3 contours: would be > is For both modalities: downstepped > declarative >> yn-question (All stat. significant.) Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 Conclusions Epistemic would conveys... Tentativeness. A high degree of speaker certainty. would be > is However, the choice of intonational contour has a stronger impact on perceived certainty. downstepped > declarative >> yn-question Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 Future Work Production study Before the textual perception study, the same 12 participants recorded each target utterance. What contours were used to convey different degrees of speaker certainty? Agustín Gravano Speech Prosody 2008

The Effect of Contour Type and Epistemic Modality on the Assessment of Speaker Certainty Agustín Gravano1 · Stefan Benus2 · Julia Hirschberg1 Elisa Sneed German3 · Gregory Ward3 1 Columbia University 2 Univerzity Konštantína Filozofa 3 Northwestern University

Extra slide Sample Stimuli A: I think the kids are tired of the water park. Maybe we should take them someplace else. B: What's the Six Flags theme park located in Gurnee? A: That {is, would be} Great America. A: What a great party! B: Yeah, but we're stuck cleaning up all the crap. A: Hey, somebody left their iPod out on the floor. B: That {is, would be} my roommate. Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 Extra slide Certainty Mean and StDev Agustín Gravano Speech Prosody 2008

Agustín Gravano Speech Prosody 2008 Extra slide Fillers token count certainty mean ± stdev downstepped 390 0.667 ± 0.435 declarative 0.605 ± 0.459 yn-question 420 1.299 ± 0.392 ANOVA: Significant difference (F(2, 1197) = 2778.2, p≈0) Tukey test: Difference is significant (95%) for ds>yn and dec>yn, and approaches significance for ds>dec. Agustín Gravano Speech Prosody 2008

Extra slide Epistemic would: Form Restricted to intransitive sentences: SUBJECT + would + VERB + POST-VERBAL CONSTITUENT Corpus study (Birner et al. ’07) 246 naturally-occurring tokens, from oral and written sources Most frequent subjects are demonstratives (79%) Nearly all verbs are be (98%) Post-verbal constituent is typically, but not necessarily, a noun phrase. Agustín Gravano Speech Prosody 2008