A new keyboard for tablet computers promises to speed up typing by a third - by ditching the traditional QWERTY layout.
Researchers at St Andrews University and Germany's Max Planck institute used computers to find the "perfect" layout for thumb-typing on a touchscreen.
The new system, dubbed KALQ, after the order the keys appear in the keyboard (in the tradition of QWERTY), allows people to thumb-type 34 per cent faster on tablets.
Touschscreen typing is slow - most users only manage 20 words per minute - because keyboards are designed for 10-finger typing on physical keyboards.
KALQ is designed for thumbs - created with computational optimisation techniques to search among millions of potential layouts before identifying the best possible one.
Dr Per Ola Kristensson, Lecturer in Human Computer Interaction in the School of Computer Science at the University of St Andrews, said: “The legacy of QWERTY has trapped users with suboptimal text entry interfaces on mobile devices."
The new keyboard will be available as a free app for Android.
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“We believe KALQ provides a large enough performance improvement to incentivise users to switch and benefit from faster and more comfortable typing.”
Dr Antti Oulasvirta, Senior Researcher at the Max Planck Institute for Informatics in Germany, said: “The key to optimising a keyboard for two thumbs is to minimise long typing sequences that only involve a single thumb. It is also important to place frequently used letter keys centrally close to each other.
“Experienced typists move their thumbs simultaneously: while one thumb is selecting a particular key, the other thumb is approaching its next target. From these insights we derived a predictive behavioural model we could use to optimise the keyboard.”
The computational optimisation process had two goals: to minimise the moving time of the thumbs and to enable typing on alternating sides of the tablet as well as possible.
The results achieved by the computational optimisation procedure was surprising: in the new keyboard KALQ, all vowels, with the exception of the letter “y” (which can be regarded as both a vowel and a consonant), are placed in the area assigned to the right thumb, whereas the left thumb is assigned more keys.
To fully benefit from this layout, participants in the user study were trained to move their thumbs simultaneously. While one thumb is approaching an intended letter key, the other thumb moves to its next target.
Finally, the authors developed probabilistic error correction methods that took into account the nature of thumb movements and statistical knowledge about the text users are typing. The error correction algorithm enabled trained users to speed up while retaining an acceptable error level.
With these improvements, users were able to reach 37 words per minute, which is the highest ever reported entry rate for two-thumb typing on touchscreen devices, significantly higher than the approximately 20 words per minute entry rate users can normally reach on a regular split QWERTY layout.