Prosody and Information Structure
Studies related to the second goal of the project were addressed particularly during 1999. With the goal of modelling the prosodic structure of system utterances, a psycholinguistic study related to the accentuation patterns of given information in spontaneous travel agent utterances was carried out. An investigation of travel-domain dialogues revealed travel-agent (=System) utterances with intonational contours characterized by prominent (focal) accents on previously given domain-related information. These accents were seen to occur on content-words in utterance-initial position. The accentuation can be assumed to be related to the interactive nature of dialogue where the travel agent links back to a domain-related concept introduced by the client (=User) and comments on it in an engaged manner. A perception test using constructed man-machine Initiative-Response dialogues where the machine (synthesized) Responses vary as to the type of accent pattern (focal vs non-focal) on the initial domain-related words was developed to test listenersí preference for accent type. Results indicated that focal accents on domain-related utterance-initial given concepts are indeed preferred, a result which has implications for the design of the utterance-generating component of man-machine dialogue systems (Horne, Hansson, Bruce, Frid (1999); Horne, Hansson, Bruce, Frid & Jönsson (1999), Horne, Hansson, Bruce & Frid (2001).
The discourse circumstances under which speakers choose to focally accent topics are further discussed in Hansson (2000).