There were keyboard layouts optimized for palmos pen input; fitaly and atomik. The most used letters are clustered in the middle so movements is minimized, theoretically speeding up the eye typing as well. It seems to be a faster entry method then using a switch like Stephen Hawking does or using a single switch morse type system at perhaps 20 wpm, but indeed much slower then having 10 fingers (switches) and perhaps two feet available at the same time.