Perceptual evaluation of synthetic speech: Some considerations of the user/System interface

With the rapid increase in the use of voice response systems in commercial, industrial, military, and educational applications, it has become important to understand how humans interact with devices that produce synthetic speech output. This paper describes a series of experiments that have examined the differences in perception between natural and synthetic speech. Our results demonstrate that important perceptual and cognitive limitations are imposed when synthetic speech is used in a variety of psychological tasks ranging from phoneme recognition to word recognition to spoken language comprehension. Moreover, these differences are manifest not only in terms of measures of response accuracy but also in estimates of the cognitive processing time required to execute responses to synthetic speech signals.