Advances in Computer Speech Synthesis and Implications for Assistive Technology

Abstract

The authors review developments in Computer Speech Synthesis (CSS) over the past two decades, focusing on the relative advantages as well as disadvantages of the two dominant technologies: rule-based synthesis; and data-based synthesis. Based on this discussion, they conclude that data-based synthesis is presently the best technology for use in Speech Generating Devices (SGDs) used as communication aids. They examine the benefits associated with data-based synthesis such as personal voices, greater intelligibility and improved naturalness, discuss problems that are unique to data-based synthesis systems, and highlight areas where all types of CSS need to be improved for use in assistive devices. Much of this discussion will be from the perspective of the ModelTalker project, a data-based CSS system for voice banking that provides practical, affordable personal synthetic voices for people using SGDs to communicate. The authors conclude with consideration of some emerging technologies that may prove promising in future SGDs.