A re-imagined touchscreen keyboard layout promises to speed up typing on tablets. The split keyboard, known as KALQ, features two 4×4 grids of keys that were generated to produce optimal thumb typing, up to 34 percent faster than typing with QWERTY, according to new research. The new layout will be available as a free Android app in May.
Research into optimal keyboard layouts is as old as QWERTY itself, a legacy inherited from 19th century typewriters. Thumb typing with QWERTY is notoriously inefficient on touchscreen tablets and phones. Starting from the basics — how a touchscreen device is held in one’s hands — an international team of researchers drew on user behavioral data and computational models to develop the new layout. The lead investigator, Antti Oulasvirta of the Max Planck Institute for Informatics, will officially unveil this research at CHI2013 on May 1.
Theoretically, the model predicts that users should be able to reach 49 words per minute with KALQ, and because the study’s subjects were non-native English speakers, typing speed could conceivably be even better in natives. KALQ was designed so the most commonly used letters are clustered, which means
the travel distances are short and both hands work roughly equally and alternately. Most of the vowels are positioned near the space bar and are handled by the right thumb, while the left thumb takes care of most of the consonants and most of the first letters of words. For lefties, the orientation can be reversed, and the key size can even be scaled for different hand sizes.
For KALQ to work, tablets should ideally be gripped horizontally, with the corners cradled in the valley at the base of the thumbs. On a 7-inch tablet (the researchers used the Samsung Galaxy Tab), test subjects had the fastest movements times and best thumb mobility with this configuration, though the grip gave them access to less tablet surface area overall.
Based on this tablet gripping strategy, the researchers used computational techniques to determine the optimal key assignments. Their model of thumb movements was trained on millions of English-language tweets that originated from mobile devices. The end result, KALQ, minimizes movement times, and worked even better when users were trained to move their thumbs simultaneously and anticipate moves by hovering the thumb over the next letter.
Novice tablet users reached typing speeds that eclipsed those achievable with QWERTY after about 10 hours of training, and continued to improve, reaching 37 words per minute. This is the fastest thumb typing speed ever reported, according to Oulasvirta and colleagues, and is 19 percent faster than typing speeds found in previous studies. The end result represents a 34 percent improvement over baseline QWERTY performance in this study’s subjects.