“Effect of Genre, Speaker, and Word Class on the Realization of Given and New Information”

1. Interspeech 2006 - Pittsburgh, PA “Effect of Genre, Speaker, and Word Classon the Realization of Given and New Information” Agustín Gravano & Julia Hirschberg {agus, julia}@cs.columbia.edu Spoken Language Processing Group Columbia University

2. Motivation • Speakers of American English tend to: • accent references to “new” information, and • deaccent references to “old” (or “given”) information. (Chafe 1974, Prince 1981 & 1992, inter alia) • Variation of prominence in “given” entities is strongly affected by the persistence of: • grammatical function (subject, object, etc.) and • position in the sentence. (Terken & Hirschberg, 1994) Agustín Gravano Interspeech 2006

3. Motivation • Possible applications: • Improve naturalness of TTS systems. • Aid ASR. • Questions: • What are other sources of variation? • What is the effect of: • speaker? • genre? • word class? Agustín Gravano Interspeech 2006

4. Main Results • Speakers vary the manner in which they realize differences in information status. • Speakers tend to produce “given” verbs with higher intensity than “new” verbs, both in read and spontaneous speech. Agustín Gravano Interspeech 2006

5. Overview • Materials and Methods • Corpus • Information status • Word classes • Features • Results • Nouns • Verbs • Discussion • Conclusions Agustín Gravano Interspeech 2006

6. Boston Directions Corpus • Hirschberg & Nakatani 1996 • Spontaneous and read monologues. • 9 increasingly complex direction-giving tasks: • Describe how to get to MIT from Harvard. • Method: • Spontaneous speech recorded and transcribed. • Speakers returned and read. • 4 speakers (3 male, 1 female). Agustín Gravano Interspeech 2006

7. Boston Directions Corpus • Mean length of tasks: • Spontaneous: 111s • Read: 84s • Excerpt from the spontaneous part of the corpus: first # enter the Harvard Square T stop # and buy a token # then proceed to get on the # Inbound um Red Line # uh subway [...] • Corpus size: • Spontaneous: ~66m • Read: ~50m • Prosody labeled using the ToBI convention. Agustín Gravano Interspeech 2006

8. Information Status • Prince 1981: • Entities are new when first introduced in the discourse. • Evoked entities are given. They are already in the discourse. • Simple definition: • A word w is given if in the current task there is at least one previous occurrence of a word with the same stem. • Otherwise, we say that w is new. Agustín Gravano Interspeech 2006

9. Word Classes • Automatically labeled the part-of-speech of all the words in the corpus using the Brill Tagger. • Categorized words into: • Nouns • Verbs • Adjectives • Adverbs • Others • Significant results only for Nouns and Verbs. Agustín Gravano Interspeech 2006

10. Features • Word acoustic features, extracted using Praat: • Max, mean, min pitch • Max, mean, min intensity • Pitch and intensity features were also normalized with respect to the mean value of: • ± 1 second around the target word, • ± 5 words around the target word, • the target word’s Intermediate Phrase. • Pause before and after the word. Agustín Gravano Interspeech 2006

11. Results: Nouns n = mean value for the new words is significantly largerthan for the given words g = mean value for the given words is significantly larger than for the new words Agustín Gravano Interspeech 2006

12. Results: Verbs n = mean value for the new words is significantly largerthan for the given words g = mean value for the given words is significantly larger than for the new words Agustín Gravano Interspeech 2006

13. Discussion: Variation of intensity in verbs • Examples: you get out of the T stop # you cross Massachusetts Avenue [...] you wanna cross Mass Ave opposite that # there's usually a bunch of cabs and and people standing around there # so # then once you've crossed it you're you're in Harvard Yard proper then you're right at the entrance to what is called the Infinite Corridor # and it's called the Infinite Corridor because it's this really long # place you can walk entirely indoors • Direct objects of ‘cross’ and ‘call’ are either deaccented or pronominalized in the second and third mentions. • With no other salient accented items in their phrases, the given mentions of these verbs are more prominent. Agustín Gravano Interspeech 2006

14. Discussion: Variation of intensity in verbs • Example: so you're going to have to transfer # you transfer by going to Government Center which is inbound • The increased intensity of the second mention of ‘transfer’ might be due to the change in its verb form. • Similar to Terken & Hirschberg, 1994: • Given nouns tend to be accented if they represent a different grammatical function from the first mention. Agustín Gravano Interspeech 2006

15. Conclusions and Future Work • Evidence of: • Speaker variation in the way they realize differences in information status. • Given verbs tend to be produced with a greater intensity than new verbs. • Nouns and verbs behave very differently. • Only preliminary results: more work needed. • Future Work: • Repeat and deepen these analyses on larger corpora of read and spontaneous speech, and in conversation. Agustín Gravano Interspeech 2006

16. Interspeech 2006 - Pittsburgh, PA “Effect of Genre, Speaker, and Word Classon the Realization of Given and New Information” Agustín Gravano & Julia Hirschberg {agus, julia}@cs.columbia.edu Spoken Language Processing Group Columbia University