Shall we mix synthetic speech and human speech? Impact on users' performance, perception, and attitude

Abstract

Because it is impractical to record human voice for everchanging dynamic content such as email messages and news, many commercial speech applications use human speech for fixed prompts and synthetic speech (TTS) for the dynamic content. However, this mixing approach may not be optimal from a consistency perspective. A 2-condition between-group experiment (N = 24) was conducted to compare two versions of a virtual-assistant interface (mixing human voice and TTS vs. TTS-only). Users interacted with the virtual assistant to manage some email and calendar tasks. Their task performance, self-perception of task performance, and attitudinal responses were measured. Users interacting with the TTS-only interface performed the task significantly better, while users interacting with the mixed-voices interface thought they did better and had more positive attitudinal responses. Explanations and design implications are suggested. Copyright 2001 ACM.