Wearable devices (e.g., smartwatches, smartglasses, and digital jewelry) featuring a touchscreen are becoming widely available to consumers. On these devices, entering text with a qwerty soft keyboard is troublesome mainly because of the very small screen space. However, qwerty keyboards have the advantage that users are already familiarized with the layout and the input technique is easy to understand. Motivated by this fact, we conduct fundamental research on this topic using 3 qwerty-based soft keyboards for 3 different screen sizes. In addition to ZoomBoard (a soft keyboard for diminutive screens), we propose a callout-based soft keyboard and ZShift, a novel extension of the Shift pointing technique.
We conducted a comprehensive user study followed by extensive analyses on performance, usability, and short-term learning. Our results show that different small screen sizes demand different types of assistance. In general, manufacturers can benefit from these findings by selecting an appropriate qwerty soft keyboard for their devices.
We also investigated 3 simple mechanisms to auto-correct typing errors as they go, at the word level: spell checker with n-best lists, language models, and a combination of both. These mechanisms have potential for wearable devices, which have limited autonomy and limited computing capabilities, even when paired to a smartphone.
In sum, this work provides designers, researchers, and practitioners with new understanding of qwerty soft keyboard design space and its scalability for tiny touchscreens, together with a series of simple but efficient error auto-correcting mechanisms for tiny touch-capable devices.