Information Status

1. Information Status

2. Varieties of Information Status • ContrastJohn wanted a poodle but Becky preferred a corgi. • Topic/comment The corgi they boughtturned out to have fleas. • Theme/rheme The corgi they boughtturned out to have fleas. • Focus/presupposition It was Beckywho took him to the vet. • Given/newSome wildcats bite, but this wildcat turned out to be a sweetheart.

3. Defining Given/New • Halliday ‘67: • Given: Recoverable from some form of context • New: Not recoverable • Chafe ’74 ’76: • Given: what S believes is in H’s consciousness • New: what S believes is not… • “Chafe-givenness” Yesterday I had my class disrupted by a bulldog/dog. I’m beginning to dislike dogs/bulldogs. • But not vice versa….

4. Why do we care about the given/new distinction? • Building a model of the discourse • What do S and H believe to be true? • What is in their consciousness now? • What is ‘grounded’? • Speech technologies • TTS: Given information is often deaccented while new information is usually accented • ASR?

5. Prince ’81: A Given/New Taxonomy • Text as set of instructions from S to H on how to construct a discourse model • Model includes discourse entities, attributes, and links between entities • Discourse entities: individuals, classes, exemplars, substances, concepts (NPs) • Entities as ‘hooks’ on which to hang attributes (Webber ’78) • Entities when first introduced are new

6. Brand-new (H must create a new entity) I saw a dinosaur today. • Unused (H already knows of this entity) I saw your mother today. • Evoked entities are old -- already in the discourse • Textually evoked The dinosaur was scaley and gray. • Situationally evoked The light was red when you went through it. • Inferrables • Containing

7. I bought a carton of eggs. One of them was broken. • Non-containing A bus pulled up beside me. The driver was a monkey.

8. Prince ‘92 • Definiteness: subject NPs tend to be syntactically definite and old • Indefiniteness: object NPs tend to be indefinite and new I saw a black cat yesterday. The cat looked hungry. • Definite articles, demonstratives, possessives, personal pronouns, proper nouns, quantifiers like all, every signal definiteness • Indefinite articles, quantifiers like some, any, one signal indefiniteness

9. But…. This guy came into the room. There were the usual subjects at the bar.

10. What’s wrong with a Hearer-centric model of given/new? • Hearer-centric information status: • Given: what S believes H has in his/her consciousness • New: what S believes H does not have in his/her consciousness • But discourse entities may also be given and new wrt the current discourse • Discourse-old: already evoked in the discourse • Discourse-new: not evoked

11. Me: I’ve decided to make an appointment with Lee Bollinger. You: Why do you want to see Bollinger? • Hearer-new --> Discourse-new (unless…?) • Discourse-new --> ? • Hearer-old --> ? • Discourse-old --> Hearer-old (unless….?) • What does this new distinction buy us? • A way to explain definiteness/indefiniteness in terms of Hearer status only • More fine-grained distinctions to explain why items are accented or deaccented

12. Inferrables: H-old, H-new, D-old,D-new • Entities S may believe H can infer based upon a previously evoked discourse entity The bus driver plowed into a store on Broadway. The driver emerged without a scratch. The bus plowed into a store on Broadway. The driver emerged without a scratch. The bus plowed into a store on Broadway. ?The bumper sticker read “How’s my driving?”. The bus plowed into a store on Broadway. *The coins spilled everywhere.

13. Containing Inferrables • The entity that evokes the inferrable is mentioned at the same time as the inferrable The tires of my car were all flat. The fingers on her right hand turned blue.

14. Empirical Analysis • What regularities can be observed for subjects? • Definite/indefinite • Hearer-old? Discourse-old? • Results: • D-old NPs tend to be subjects • D-old pronouns more likely to be subjects than other D-old NPs • D-old non-pronouns+Inferrables seem to pattern together\

15. Discourse-old predicts subjecthood better than Hearer-old status or definiteness

16. How does this help us in analyzing/generating a discourse? • Analysis: • How can we identify sentence subjects? • How can we decide what is in S and H’s discourse models? What would this tell us about what they know? Believe? • Generation: • How do we produce natural-sounding sentences?

17. The Federal Aviation Administration is moving to impose new maintenance standards on older airliners, but industry officials say the agency needs to do a more thorough job of inspecting the aircraft. A Senate aviation subcommittee examined the problem of aging airliners at a hearing on Tuesday, a session that also produced a warning from the panel's chairman that tougher government regulations might be on the way. The chairman, Wendell Ford, Democrat of Kentucky, told reporters after the session that Congress should consider requiring the F A A to force an increase in the frequency of inspections of older aircraft, require replacing certain parts rather than examinations of them, and set training and experience standards for airline inspectors and mechanics. Ever since the roof of a nineteen year old Aloha Airlines Boeing seven thirty seven peeled off over Hawaii last April, sweeping a flight attendant to her death, attention has been focused on the older aircraft. The F A A and the nation's major airlines agreed in February to more than eight hundred million dollars worth of improvements to be made on thirteen hundred older Boeing jetliners. The goal is to eliminate certain routine inspections in favor of design improvements and a schedule for regular replacements of certain parts. On Tuesday, Anthony Broderick, the F A A's associate administrator for regulation, said that late this month or in early May, the agency will propose rules that would require more than one hundred sixty structural changes in Boeing seven twenty sevens, seven thirty sevens and seven forty sevens.

18. The last year has been a difficult one for the older members of the U. S. airline fleet. Nine people died in December when a nineteen year old United Airlines Boeing seven forty seven broke open over Hawaii; a twenty two year old Eastern Airlines Boeing seven twenty seven landed without casualties after a hole opened in its fuselage while flying over West Virginia; and an eight year old Piedmont Airlines seven twenty seven lost an engine during takeoff from Chicago. The average age of airliners used by U. S. carriers is twelve point seven years, up from eight years in nineteen eighty. It is expected to be fifteen years by the year two thousand, because there are backlogs of orders for new aircraft and an ever growing passenger load. At the hearing, officials from the F A A, the airlines and the aircraft manufacturing industry assured lawmakers that improvements were being made constantly in how aircraft are constructed, maintained, tested and inspected. But Benjamin Cosgrove, vice president for engineering for Boeing Commercial Airplanes, a Boeing subsidiary, said F A A inspectors should spend more time examining airlines and less time checking paper work, and complained that F A A fines for maintenance infractions can be counter productive. Cosgrove said, ``Routine use of such penalties tends to drive problems underground and communication in the industry suffers ''. Claude Kizer, engineering vice president for the Air Transport Association, which represents the major airlines, said the group is considering whether inspectors and mechanics for all carriers should be required to meet uniform training standards. This angered Ford, who asked: ``Why should there be any question but that you go ahead with strict training and education across the board?''

19. Next • Besides information status, what features help us decided whether a discourse is coherent or not? What is discourse structure? How do we recognize it -- automatically? • Read: J&M Ch 18 2,3,5; Grosz&Sidner ‘86 • HW3 assigned