Prompt constrained natural language-evolving the next generation of telephony services

The paper describes the design and development of an automated car reservation system using large vocabulary natural language speech recognition. Reservations were made over the public switched telephone network by calling an 800 number from anywhere in the United States, and car availability checked in real-time with a major international car rental company. This system was designed to support first time users without requiring extensive written instructions, using current state-of-the art product-grade speech recognition technology. A prompt constrained natural language (PCNL) paradigm was used to encourage users to respond within the constraints of the recognition technology. The results of an extended technology trial demonstrate the viability of services using automatic speech recognition to support transaction processing services. The extension of this technology to new domains is described