Constructing Chinese characters: keypad design for mobile phones

Increased use of mobile phones and associated services in China highlights the need for effective Chinese input methods for mobile devices. Mapping thousands of characters to a standard telephone keypad is a significant challenge. Structure-based methods provide an appealing known-character/known-code solution, but assigning multiple strokes to each key forces users to learn new, often unfamiliar, mappings. Using an established stroke input method, our study revealed important effects of keypad legend on performance. Novice user performance was evaluated with several alternative keypad designs. The results confirmed that both abstract symbols and concrete examples helped improve the usability of the keypad in Chinese text-entry tasks. Further, combining abstract symbols and concrete examples resulted in performance nearly tripling as compared to the original design. The stroke-to-key mapping accuracy also increased significantly. Handwriting analysis confirmed that the reduced errors are directly associated with the keypad-based text-entry technique.