Watch-top text-entry: can phone-style predictive text-entry work with only 5 buttons?

This paper presents an initial study into the viability of text entry on a watch face using four alphabetic buttons and a central space key. The study includes a technical evaluation of likely error rates using a large text corpus and user studies on palmtop emulated mobile phone and watch. The results, though in favour of the phone pad, are encouraging and show such a method is feasible