  Speech is becoming increasingly popular as an interface modality, especially
in hands- and eyes-busy situations where the use of a keyboard or mouse is
difficult. However, despite the fact that many have hailed speech as being
inherently usable (since everyone already knows how to talk), most users of
speech input are left feeling disappointed by the quality of the interaction.
Clearly, there is much work to be done on the design of usable spoken
interfaces. We believe that there are two major problems in the design of
speech interfaces, namely, (a) the people who are currently working on the
design of speech interfaces are, for the most part, not interface designers and
therefore do not have as much experience with usability issues as we in the CHI
community do, and (b) speech, as an interface modality, has vastly different
properties than other modalities, and therefore requires different usability
measures.
