In ACL/COLING-98 Workshop on Discourse Relations and Discourse Markers Lexical, Prosodic, and Syntactic Cues for Dialog Acts

The structure of a discourse is reflected in many as-pects of its linguistic realization, including its lexi-cal, prosodic, syntactic, and semantic nature. Multi-party dialog contains a particular kind of discourse structure, the dialog act (DA). Like other types of structure, the dialog act sequence of a conversation is also reflected in its lexical, prosodic, and syntac-tic realization. This paper presents a preliminary in-vestigation into the realization of a particular class of dialog acts which play an essential structuring role in dialog, the backchannels or acknowledge-ments tokens. We discuss the lexical, prosodic, and syntactic realization of these and subsumed or re-lated dialog acts like continuers, assessments, yes-answers, agreements, and incipient-speakership. We show that lexical knowledge plays a role in distinguishing these dialog acts, despite the wide-spread ambiguity of words such as yeah, and that prosodic knowledge plays a role in DA identifica-tion for certain DA types, while lexical cues may be sufficient for the remainder. Finally, our investi-gation of the syntax of assessments suggests that at least some dialog acts have a very constrained syn-tactic realization, a per-dialog act ‘microsyntax’.