LetterEase: Improving text entry on a handheld device via letter reassignment

LetterEase, a new technique for text entry on a small handheld device is described. Indeed, the current 12-button text entry keypad causes typing overhead as 26 alphabet letters are assigned to only 8 buttons (2-9). The LetterEase method uses letter-frequency data from SMS text messages collected from real situations and the moving distance between buttons with thumb use. We first discuss how to implement this LetterEase method, and then present the results of a controlled experiment comparing LetterEase to the conventional multitap method and the two-letter multitap method that was designed as a control letter assignment. The results showed that both less keystrokes and less errors using LetterEase were identified. In addition, despite slower text entry speed than that of the conventional multitap method, in effect, the users experienced LetterEase lessened the gap more readily during the course of the experiment as fast as the conventional multitap method.

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