Modeling conversational styles in Italian by means of overlaps

Conversational styles vary cross-culturally remarkably: communities of speakers – rather than single speakers seem to share turn-taking rules which do not always coincide with those shared by other communities of the same language. These rules are usually responsible for the smoothness of conversational interaction and the readiness of the attainment of communicative goals by conversants. Overlaps constitute a disruptive element in the economy of conversations: however, they show regular patterns which can be used to define conversational styles (Ford and Thompson, 1996). Overlaps constitute a challenge for any system of linguistic representations in that they cannot be treated as a one-dimensional event: in order to take into account the purport of an overlapping stretch of dialogue for the ongoing pragmatics and semantics of discourse, we have devised a new annotation schema which is then fed into the parser and produces a multidimensional linear syntactic constituency representation. This study takes a new tack on the issues raised by overlaps, both in terms of its linguistic representation and its semantic and pragmatic interpretation. It will present work carried out on the 60,000 words Italian Spontaneous Speech Corpus called AVIP, under national project API the Italian version of MapTask, in particular the parser, to produce syntactic structures of overlapped temporally aligned turns. We will also present preliminary data from IPAR, another corpus of spontaneous dialogues run with the Spot Differences protocol. Then it will concentrate on the syntactic, semantic and prosodic aspects related to this debated issue. The paper will argue in favour of a joint and thus temporally aligned representation of overlapping material to capture all linguistic information made available by the local context. This will result in a syntactically branching node we call OVL which contains both the overlapper's and the overlappee's material (linguistic or non-linguistic). An extended classification of the phenomenon has shown that overlaps contribute substantially to the interpretation of the local context rather than the other way around. They also determine the overall conversational style of a given community of speakers with cultural import.