ACOUSTIC AND LANGUAGE MODELING OF HUMAN AND NONHUMAN NOISES 
    FOR HUMAN-TO-HUMAN SPONTANEOUS SPEECH RECOGNITION
  
              Tanja Schultz and Ivica Rogina
                     <tanja@ira.uka.de>

             Interactive Systems Laboratories 
             University of Karlsruhe (Germany)
             Carnegie Mellon University (USA)
                 
                  published at: ICASSP 95

In this paper several improvements of our speech-to-speech 
translation system JANUS-2 on spontaneous human-to-human 
dialogs are presented. Common phenomena in spontaneous speech 
are described, followed by a classification of different 
types of noises. To handle the variety of spontaneous effects 
in human-to-human dialogs, special noise models are introduced 
representing both human and nonhuman noises, as well as word 
fragments. It will be shown that both the acoustic and the 
language modeling of these noises increase the recognition
performance significantly. In the experiments, a clustering of 
the noise classes is performed and the resulting cluster 
variants are compared, thus allowing to determine the best 
tradeoff between sensitivity and trainability of the models.