Why Only 30?
As you may have noticed, my keyboard designs have been limited to only the central 30 characters — on a traditional QWERTY keyboard these keys include the alphabet, period, comma, semicolon and slash. Why have I not expanded my program to include other keys? It is certainly not because those keys are in optimal positions already. Many of the keys outside of the main 30 have the very worst placement. So why not try to optimize them as well?
1. They are too hard to re-learn.
I have tried to learn a layout where the all of the keys were optimized, but it did not go well. I found myself completely unable to switch back and forth between it and QWERTY. The layout was simply too complicated, so I ended up just putting all the outlying keys back into their original positions.
2. Many of them rely on aesthetics that a computer program won’t notice.
Look at the number keys. They are neatly lined up in an easy-to-remember fashion. However, their order of frequency is not so simple. A computer algorithm would end up completely jumbling these numbers. It would also likely not put the open and close brackets next to each other, as well as numerous other aesthetic benefits. A computer program would simply miss these little nuances.
3. That program would be harder to write.
Yes, I admit it, I am somewhat driven by laziness. This new program would require modification of many parts of the program, and would make it harder to evaluate the keyboard’s score. The set of digraphs used to score the keyboards would be larger, causing both accuracy and program efficiency to suffer. Evaluating the score would require taking into account all four (or even five) rows, and the extra keys on the side. The score evaluation process would be much more complicated, and therefore harder to get right. Overall, I didn’t see the benefits as worth the effort.