Dialogue Acts Recognition - Man-Machine Dialogue: Design and Challenges - page 116

Here we have analyzed “how long with this itinerary which seems shorter?”
as a single discursive segment, which is thus affected with a composite act with
two aspects. Another possibility would have been to consider two segments,
along criteria which have less to do with syntax (there is only one sentence)
and more to do with function or communication, and we invite the reader to
refer himself/herself to functional segments in [BUN 11]. The result is the
same with both approaches: the system is confronted with two acts, and it can
react to one or the other, or even to both. The advantage of the solution which
considers the utterance as a single segment is that it emphasizes one act over
the other, which is harder to do if it considers two autonomous segments. The
direct act matching the question in the main clause is emphasized compared
to that of the comment, due to the fact that it is linked to a main clause and
not a subordinate or relative clause. Thus it is mostly syntactic criteria that
take precedence here. There are, however, situations in which a single segment
clearly leads to the identification of a composite act. This is the case for the
utterance “what about eight o'clock?” as an answer to the query “do you have a
train for Paris tomorrow morning?”. It is a query from the system which relates
to a time, in reaction to the user's query. Yet the fact that a time is mentioned
proves that the system has understood the query: not only does it answer in
the affirmative (if the answer had been negative, this utterance would not have
been possible), but it also requests a precision to validate the reservation. We
thus have a composite act or, to take up the point of view in [ASH 01], a
complex act including an elaboration relationship between the two utterances.
Without questioning the classification into three main speech acts which
relevance theory establishes, this type of example shows that natural language
does not fall into totally compartmentalized categories. The interpretation
suggested here for the introduction example is more limiting. To do the job
properly, we would have to integrate the aspects of the speech turns, of the
grounding which would take into account the previous utterances and, in
general, of all the communication functions which occur in a dialogue, such
as the management of time and the task in progress.
7.2. Identification and processing of dialogue acts
7.2.1. Act identification and classification
In MMD, determining the nature and typology of speech acts as well as
dialogue acts must be able to cope with two potentially contradictory goals.