Maximum listening speeds for the blind

Proceedings of the 9th International Conference on Auditory Display (ICAD), Boston, MA, July 7-9, 2003.Blind people usually use voice output using a computer, however, there is little objective data about how fast or accurately they can obtain information in a fixed amount of time In this paper, we describe the highest and the most suitable listening rate for the blind based on our human factors experiments, aiming at producing a kind of indicator for use by developers. We experimented with the highest and the most suitable listening rates for blind users with objective and subjective test methods. The results showed that the advanced blind testers could listen to the spoken material at speeds 1.6 times faster than the highest rate of the tested TTS (Text-to- Speech) engine. This indicates that the currently available TTS engines should support faster rates. It also showed that the highest rate often changes depending on the difficulty of the sentences and words. These results would be valuable and useful indicators for developers to design applications for the blind and to improve the nonvisual user interfaces