Semantic Analyses and Representations - Man-Machine Dialogue: Design and Challenges - page 79

the system which made a mistake. Moreover, the information structure also
makes sense beyond the boundaries of the utterance, and we can thus add a
topical progression characterization to semantic analyses, which describes
how topics follow one another in a dialogue and what relations are built
between one another. In MMD, information structure identification and
topical progression allow us to better manage the way in which the current
utterance can be inserted into the dialogue history, and thus better manage the
dialogue and achieve satisfying the task in a more efficient manner, for
example by coming back to the main topic if the dialogue has deviated too far.
5.1.2. Oral and written languages
Oral and written languages are not only different due to their means of
expression, to prosody with the prominence accent we have just mentioned,
but also by their use of syntax and morphology: there are many different
graphemes and phonemes, different marks of the plural, as well as the
importance in enunciating the links (“liaisons”) between words 1 , see
section 2.2.1. Different language levels can coexist in oral language.
Utterances such as “could I get a train for Paris?” can alternate with “a train
for Paris, is that possible?” which at the end provides the system with a
multitude of possibilities [COH 04]. The oral language ignores some errors
more easily than the written language such as tense agreement or other rules
with verbs. The oral language is characterized by noise (hesitation and
interjection), distortion (repetition, specification with no cancellation and
correction with cancellation), fragmentation (starting again after an
interruption, juxtaposition, dislocation and sentence fragment) and ellipsis
phenomena which can appear in written language, but much less frequently,
and lead to diversified syntactic structures: “what time for the Paris train?”,
“at night, the Grenoble train, where does it stop?”, “is it the shortest journey,
the one going through Meudon?” or even “I'd like two of them, those tickets”.
The consequences for MMD are the increase of potential structures that the
system has to know in order to process the input sentences.
1 In French, consonants which would normally be silent at the end of a word are sometimes
vocalized when this word is followed by another word starting with a vowel. Thus, while the
final “s” is not pronounced in “moins” (less), it will turn into a “z” sound when placed in front
of “agréable” (enjoyable).