Application of isolated word recognition to a voice controlled repertory dialer system

In this paper we describe a speaker trained, voice controlled, repertory dialer system. The main elements of the system include: 1. A real-time speech analyzer that detects the presence of speech on the input line, and analyzes the speech to give features appropriate for a word recognizer. 2. An isolated word recognizer that decides which of a set of words was spoken. 3. A voice response system to provide spoken commands to the user to guide the use of the repertory dialer system. 4. A dialer (simulated) to outpulse the desired telephone number. The repertory dialer system is implemented on a minicomputer with a high speed array processor performing the real-time operations. The vocabulary for the system consists of 7 command words, 10 digits, and any number of names up to some specified maximum Recognition is performed on one or more subsets of the vocabulary, depending on fine state of the system. To train the system the user is requested to speak each of the vocabulary words twice to provide reference templates for the system. Following training, the system can dial the telephone number corresponding to any name in the repertory, or it can dial a 4 digit telephone extension spoken as an isolated string of digits. The system was tested extensively by 6 talkers (3 male, 3 female - 3 of whom were naive and 3 experienced users) over a three week period. A total of 4620 words were spoken and during the course of the test there were no recognition errors. A request for a repeat of a spoken word occurred about 2% of the time. These tests demonstrate the reliability and robustness of this voice repertory dialer system.