Designing Effective Speech Interfaces

Suitable Tempo

Suitable Tempo, law #15, states: The interface will operate at a tempo suitable to the user.

Human Factors

If the pace of the conversation with the computer or the speed with which text is spoken is too slow, users become frustrated and try to speed up the interaction, which may result in more errors.

Because speech interfaces are temporal, with events occurring one after another, the issue of suitable tempo or pacing is important. If the pace of the conversation with the computer or the speed with which text is spoken is too slow, users become frustrated and try to speed up the interaction, which may result in more errors. If, on the other hand, the pace of the interaction is too fast, then users may not understand what is being spoken or what they are supposed to act on.

Technology Considerations and Implications

Speech interfaces must be prototyped, iterated, and tested with real users to assure if the tempo or pacing is appropriate. It is hard to simulate small pieces of this. Since a particular user's path can differ from another's, it is necessary to test real people trying to do real tasks with the real system, not a low-fidelity prototype.