Existing devices for communicating information from people to computers are either bulky, slow to use, or unreliable. The conventional keyboard requires the user to make one or two gestures per character (one for lower-case and two for upper-case characters). All ten human digits are used, and a large 12-inch by 4-inch physical device is required; only one of the ten digits is used per gesture.
Dasher is a new interface incorporating language modelling and driven by continuous two-dimensional gestures, \eg a mouse, touchscreen, or eye-tracker. Tests have shown that this device can be used to enter text at a rate of up to 39 words per minute during a dictation task, compared with typical ten-finger keyboard typing of 40-60 words per minute.
We also show that Dasher can be used as a mobile text entry device. On a hand-held personal organiser, users enter text with a stylus and a touchscreen.
Dasher can be used with an eye-tracker as a hands free text entry system. Expert writing speed is currently 20 words per minute. We hope that this system will be useful to people with limited access to a keyboard.
The writing speed of Dasher depends of the quality of the language model. The Dirichlet Language Model, Boltzmann machines and neural networks are all investigated as better language models for use in Dasher.
Dasher is still under development; we think it shows promise as a keyboard--less text entry system both in its absolute writing speed and ease of use.