The system for spoken queries in the Slovenian language over the telephone consists of four basic modules: the word recognition module, the linguistic analysis module, the dialogue manager and the speech synthesis module. The application domains of the experimental system are air-flight information, so the system uses the Adria Airways flight timetable. The system provides the users with flight timetable information over the telephone.
The word recognition module uses acoustic models of Slovenian polyphones and bigram and trigram stochastic language models.
For linguistic analysis of the recognized sequences of words, a DCG based parser is implemented. The parser extracts the most important words needed for a database query and transforms it into a form, which is read by the dialogue manager.
The task of the dialogue module is to interpret the meaning of the input utterance and to produce an appropriate answer, or to initiate a clarifying question.
The answers, which are generated by the dialogue manager are synthesised using the speech synthesis module. The speech synthesis module involves grapheme-to-phoneme transcription and prosodic modelling. Basic speech units, diphones, are concatenated using the TD-PSOLA technique.
The telephone based system is so designed that it can be easily adapted to a number of different speech dialogues and application databases.