Real-time large vocabulary spontaneous speech recognition for spoken dialog systems

This paper describes the method for modifying the baseline speech recognition system to be suitable for a use in spoken dialog system with mixed initiative and natural user´s input. We present three approaches for extending the recognition vocabulary to ensure the spoken dialog system is able to recognize all entities in the given domain. The colloquial text normalization method is proposed. The experiments performed on spontaneous speech corpus suggested that the proposed method is very important for languages where the formal written language and a common colloquial speech are very different. The overall word error rate was reduced by 16.7%.