JOURNAL OF MULTIMEDIA (JMM)
ISSN : 1796-2048
Volume : 2    Issue : 3    Date : June 2007

Lexical Structure for Dialogue Act Recognition
Pavel Král, Christophe Cerisara, and Jana Klecková
Page(s): 1-8
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Abstract
This paper deals with automatic dialogue acts (DAs) recognition in Czech. Dialogue acts are
sentence-level labels that represent different states of a dialogue, such as questions, hesitations, ...
In our application, a multimodal reservation system, four dialogue acts are considered: statements,
orders, yes/no questions and other questions. The main contribution of this work is to propose and
compare several approaches that recognize dialogue acts based on three types of information:
lexical information, prosody and word positions. These approaches are tested on a Czech Railways
corpus that contains human-human dialogues, which are transcribed both manually and with an
automatic speech recognizer for comparison. The experimental results confirm that every type of
feature (lexical, prosodic and word positions) bring relevant and somewhat complementary
information. The proposed methods that take into account word positions are especially interesting,
as they bring global information about the structure of the sentence, at the opposite of traditional
n-gram models that only capture local cues. When word sequences are estimated from a speech
recognizer, the resulting decrease of accuracy of all proposed approaches is very small (about 3 %),
which confirms the capability of the proposed approaches to perform well in real applications.

Index Terms
dialogue act, language model, prosody, sentence structure, speech recognition