Dialogue Acts Recognition - Man-Machine Dialogue: Design and Challenges - page 112

hearer do something and in which we find queries and orders; commissives,
which commit the speaker to a future action; expressives and declarations.
This theory is the focus of many variations and adaptations, for example that
by Clark [CLA 96] who considers the following types of act: assertion, order,
closed question, promise, offer, thanks, compliment, greeting and farewell. In
general, the different approaches and criteria that lead to the determination of
one list of acts rather than another are presented in [TRA 00].
Sperber and Wilson [SPE 95], within the context of their cognitive and
pragmatic approach to dialogue, suggest to abstract the categories into
“telling to” (which we will call order), “asking” (query) and “saying that”
(assertion), which focus on what the system has to identify to interpret the
utterance. These three types of speech act are not based on the utterance's
syntax, as the beginning of the chapter might have led us to believe, do not
involve conditions as J. Searle's do, and, at least for humans, can be identified
thanks to simple linguistic tests: adding “please” allows us to test the order,
adding “tell me” at the beginning of the utterance allows us to test the query
and adding “after all” allows us to test the assertion. The syntax provides
hints without any syntactic structure being linked to a type of act: “may I
have a ticket for Paris?” as a query, mostly satisfies the test of the “please”
characterizing an order. Prosody also provides hints, with, for example, a
rising (or rather a constant, but not a sinking) intonation outline allowing us to
interpret “you have tickets for Paris” as a query rather than an assertion. As
for the last example, the act of querying, especially if the prosody is not very
strong, can, however, not be visible, at least much less than it is in “do you
have tickets for Paris?”. Because of this remark [KER 12], we could find a
distinction between the illocutionary value and the illocutionary force: in both
cases, the value is a query, whereas the force is rather weak in the case of the
assertive form and strong in the case of the querying form. This allows the
system to better characterize the utterance's speech act, and thus react in a
relevant manner.
Beyond speech acts, the dialogue implements acts linked to the progress
and modalities of communication. We have already seen that the possibility
for gesture acts has led us to talk of dialogue acts. This term is also used to
refer to acts which can be understood in a dialogue context, that is, taking the
previous utterances into account. Thus, due to its limited semantic content, an
utterance such as “yes” is allocated as an assertion speech act, but is more
precisely modeled by a dialogue act of an acknowledgment type or answer to