Dialogue Acts Recognition - Man-Machine Dialogue: Design and Challenges - page 113

a query type when we consider that the previous utterance is either “I want a
first class ticket” or “are there any seats left in the next train for Paris?”. Thus
integrating dialogue aspects into the notion of an act can be problematic, and
some authors refuse this vision, considering that links between utterances are
carried out at a different analysis level, in dialogue management (see Chapter
8). Nonetheless, it remains that a speech act is understood in a dialogue, which
Grisvard [GRI 00, p. 102] shows with the example “you erase the sequence”,
which, preceded by “what happens if I press OK?” can be interpreted as an
assertion, whereas if it is preceded by “OK, so what do I do now?”, can be
interpreted as an order. This type of example shows why it is indispensable
to refer to the dialogue history. Finally, dialogue acts can be considered as
constituting a category of conversational acts [JUR 09], with the category of
speech turn acts, grounding acts (acknowledgment, acknowledgment request,
repair, repair request, continuation, cancellation, etc.) and argumentation acts
(elaboration, clarification, opposition, etc.). This more global point of view
may become broader by integrating the possibility of collaborative acts, that
is, carried out cooperatively by the speaker and the hearer, such as when an
utterance by the first completes the utterance by the second.
In the end, an utterance such as “how long with this itinerary which seems
shorter?” can carry several conversational acts: not only explicit acts such as
the query on the journey time and the comment on the fact that it seems to be
shorter (section 7.1.2), or simply the fact of speaking following the dialogue
system's act, but also tacit acts such as the one corresponding to a grounding
of the utterance “here are the possible itineraries”: it is because the user
understood this utterance well that he/she can allocate the status of
alternatives answering his/her initial query to the graphical elements
appearing on the screen. Moreover, the act of acknowledging the previous
utterance is also a tacit act involved here. We then reach the notion of
multifunctional act [BUN 11], which we will refer to later as a composite act
(section 7.1.3).
7.1.2. The issue with indirect acts
In the example of the introduction mentioned above, “which seems shorter”
is a relative clause which can be interpreted as the proposition “this itinerary
seems shorter”. With its assertive form, the comment made by the user can
appear to have little importance, or at least not to concern the system but be