Evaluating the Quality of Synthetic Speech

The utility of text-to-speech systems depends on two aspects of their performance: intelligibility and nateralness. Evaluation of these aspects of synthetic speech provides important information about the performance of a speech synthesizer in comparison to competing products. It can be important for developers to understand where the realitve strengths and weaknesses of a particular synthesizer are so they can assist in development as well as marketing. Diagnostic evaluation directly can assist in the development effort by pinpointing specific problems in synthesis that can be redressed by engineering solutions. This chapter will outline the prinicles that govern the design of tests to measurethe performance of a text-to-speech system. Moreover, we will discuss the factors that influence performance on these tests. Finally, we will review some performance comparison tests used for text-to speech systems.