As we know, Colemak is an excellent layout. One of the first optimized layouts, it has stood the test of time. Although some have proposed alternative layouts to address perceived flaws in Colemak, these tend to solve some problems at a cost of introducing new weaknesses.
In my personal view, Workman is a good example. It does a nice job of making better use of easier to reach keys, but at a cost of more same-finger bigrams and some awkward-looking placements, such as its D.
But instead of throwing the baby out with the bathwater, what if we asked the question what minor mods could be made to Colemak which address possible criticisms, but without adversely impacting on Colemak's strenghts? So the purpose of posting this topic is to look at some possible options.
Basically, following on from discussing the D>P>G mod, the question I am asking is: What changes can be made subject to this strict rule: Starting from base Colemak, no key can change fingers. Consequently, any such change would (i) leave same-finger bigrams unaffected and (ii) be much easier to learn than a change that required finger changes.
The main target here are the index fingers, given they cover 6 keys, and that's where potential improvements can be gained.
I have seen some keyboard diagrams where people rate each key position by effort to measure ease of typing. These are no doubt somewhat subjective - but perhaps it's possible to get some consensus at least on the preferred order of keys on a given finger. Starting from the index finger "home" position, I propose this order would be: (1)bottom-row, (2)top-row, (3)middle-row-centre-column, (4)bottom-row-centre-column, (5)top-row-centre-column, i.e.:
2 5 5 2
T 3 3 N
1 4 4 1
So now let's look at the actual frequency of letters.
As you can see, the correlation between key effort and frequency is far from optimal. This in my view accounts for the most common criticisms of Colemak.
Let's look at some options to improve things:
1. The D > P > G switch
This is the mod that started me thinking about this topic. A clockwise rotation of those three keys, to leave D and G in improved positions. P is worse off but is least frequent of the 3.
+ more comforable D and G
+ G returns to Qwerty positon (one less changed key for new users)
+ Left centre-column usage reduced from 7.76% to 5.44%
- 3 keys change from standard Colemak
2. The D > V > B > G switch
For this change, I think the Angle mod is a pre-requisite. The common D moves to the easiest available spot (C key on a standard board).
+ optimal D and easier G
+ G returns to Qwerty positon
+ Left centre-column usage reduced from 7.76% to 4.49%
- 4 keys change from standard Colemak
- Breaks the standard "Z X C V B" pattern
3. Move all 6 keys strictly according to effort/frequency stats
+ optimal arrangement according to stats
+ Left centre-column usage reduced from 7.76% to 4.40%
- Breaks the standard "Z X C V B" pattern - position of V bad for paste shortcut
- only B retains Qwerty position
Personally I would rule this one out.
The right hand index finger keys are already closer to what the effort-frequecy stats suggest as optimal. The only conceivable change to produce a benefit is:
The H-M switch
A simple switch to move H to the easily reached M position.
+ Easier to type H
+ Elimate the much compained-of HE bigram. I make that HE/EH accounts for 3.49% of bigrams, ME/EM accounts for 1.15%
- Moves two keys which were unchanged from Qwerty.
Of course, making any change at all technically makes it no longer Colemak, but by limiting ourselves to modest changes, all same-finger, I think the result could still be considered as in the Colemak "family".
For the left hand, the D>P>G switch is a quick win with very little disadvantage, especially for new Colemak users who would have to relearn one fewer change (G).
Q W F D P J L U Y
A R S T G H N E I O
Z X C V B K M , .
However, if we are talking about the best available Colemak-like layout, then I think the D>V>B>G switch used with the angle mod wins. The angle mod would be compulsory with this arrangement. By also combining with the H-M switch, it also gives a certain pleasing symmetry regarding the former centre-column H and D:
Q W F P B J L U Y
A R S T G M N E I O
Z X C D V K H , .
It does require 6 changed keys from base Colemak, which is more than ideal, but at least all are on the same finger. With its easier to type keys, but retaining Colemak's home keys and excellent same-finger bigram stats, perhaps this could be a very pleasant evolved Colemak? Anyone think it's worth a try?