Keeping multiple layouts put unnecessary heavy strain on your brain and muscles. Similar to drawing circle in one hand and drawing square in another.

Luckily, there is a solution for your concern. For working at Qwerty computer, you can use colemak.exe. Just run it and you can type Colemak without installing anything.

http://www.ryanheise.com/colemak.exe

Ah, that gives me a lot of hope!  Thanks!

I've been researching this myself because I plan on doing something similar (learn and get decent at both Dvorak and Colemak).  Not many places had real experiences I was looking for--probably the most useful I saw was several of the comments in the following Slashdot article:

http://ask.slashdot.org/story/05/07/10/ … and-dvorak

That's for QWERTY + Dvorak users, but if a layout combination that different is possible to remember and easily switch back and forth mentally at will, then surely it can apply to two similar layouts possibly even easier (fewer different keys to mix up and practice on).  It seems that most people recommend learning the other layout and using it exclusively until you know it well enough to type it properly, and then get re-acquainted and back up to speed with your old layout.

Some might argue that this is unnecessary with Colemak's similarity to QWERTY, but I'd say it could still be beneficial; you will probably go through less confusion and learn the layout faster (and better) if you don't keep typing your known layout while trying to learn another.  The disadvantage would be requiring a few weeks to a month of time to learning a new layout, then finally re-learning the original (which should still be somewhat fresh somewhere in your mind, you'll just have to dig it back up)... during which time your typing skills will probably go from abysmal to barely even tolerable.

BUT... Like I said, I'm just researching this myself, I don't yet have any actual experience.  I learned Dvorak well enough by three or four weeks that I could have recalled my QWERTY ability by then, and that is what I originally planned to do.  The problem is, Dvorak just felt so good by comparison I didn't care, and because Dvorak is available as a secondary layout on pretty much every computer out there, I decided to just focus on Dvorak exclusively and eventually continue on with my plans of other layouts.  I made absolutely no attempt to preserve my QWERTY skills when the time came, and I could probably still dig them up (hasn't been that long--maybe 1 ½ months) if I really wanted to, but I still don't want to.

Well, for what it's worth, after a bit of trial and error and a few retries, I managed to type "the quick brown fox jumps over the lazy dog" in QWERTY with very few mistakes (each one correctable with a bit more thinking and no looking down).  It was pretty slow, but I did it--and I most definitely could *not* do that very easily (or as fast) on my first week and a half or even two weeks of Dvorak (too much confusion...)!  So it is clearly still there--and honestly, it seems as if just remembering the problem keys (there aren't many) to prevent mistakes and then getting back to speed shouldn't be too hard.  Surely more problem keys will pop up here and there in real typing--that's inevitable, but they'll go away with time.

It was relatively easy and effortless.  It seemed to take the longest for me to think about and remember the V key's location for some reason and I mix the T/Y keys up frequently (did that at the beginning of Dvorak too due to their locations).  There are a few other problem keys (D, G, B, N, sometimes Z...), but those seem to be the biggest.  In actual typing, I may need to use a picture or look down at the keyboard as a guide at first, but even so I have a feeling it would all come back very quickly as I get the feel again for common letter sequences, and even then it still seems to be a bit faster than I was on my first week of Dvorak.

I'm just not so sure that layout is worthy at this point... but that little exercise had some nicely reassuring and interesting results.  If I wanted, I could probably be back to a decent speed in a very short amount of time, and not lose Dvorak (or even touch the skills I've built up for it).  Needless to say, though, I am typing this post on Dvorak, and much faster than I did that pangram in QWERTY.  Maybe I will consider getting up to a decent QWERTY speed (35-40 WPM) for when absolutely required and for nostalgia purposes (ie. running FreeDOS in either DOSEmu or a virtual machine, or playing classic PC games in DOSBox), with the secondary benefit of using other computers very briefly or when unable to switch layouts.  It would also provide a third benefit of keeping Colemak's and QGMLWB's symbol and punctuation keys in memory, and--even better--also make learning Colemak in the first place much easier.  Hmmm... very tempting, actually. :)

So, there you go... it seems that what you "forget" can in fact easily be dug back up and re-practiced with minimal trouble, and with nowhere near the amount of confusion created by learning a new layout.  They do also seem easily switchable in my mind.  The major confusion seems to be typing in Dvorak, as I intend to, while forgetting to switch layouts in the operating system (or the exact reverse; typing in QWERTY as intended when forgetting to switch the computer to it).  Now I'm just wondering whether I should bother fully re-acquiring my QWERTY abilities or not... it's actually kind of tempting, even if I have no intention of typing at my original speeds in it; I would rather use a more comfortable layout for higher speeds.  It would also make typing "loadkeys dvorak" easier in Finnix and other Linux system rescue and maintenence CDs, which are of course all QWERTY by default.

Keep in mind, though, that Colemak has far fewer changed keys to remember, so you can likely get back up to speed after using it even faster.

Update: This seems to work so well, in fact, that it even brings back my old QWERTY bad habits and cheats that I tried to (and did) eliminate when I learned Dvorak, but they only affect me when I'm using QWERTY.  I would probably try to "unlearn" those if possible before increasing my speed.

That's one thing I like with Colemak you know - less irritation in situations like those! ;)

Yep... I'm with pinkyache on this one.  Operating systems should strive to make switching the layouts as simple and quick as possible.  Both for the logged-in user and system-wide (ie. the log-in screen).

With my trial, Windows 8 failed miserably at the log-in screen; it seemed that the only way to get it off QWERTY from my searching was some obscure registry hack.  Changing it for the current user was slightly better, in that once your preferred keyboards are set up an icon appears in the system tray to easily switch between them.  The problem with this is that you have to first go through the control panel to set all this stuff up in the first place--on every machine--and ever since Vista, the control panel has been an illogical, convoluted mess (even when switched to "classic" large icons view).

With Linux, well, it varies by distribution, but KDE4's process of changing the user's keyboard is similar to the way Windows does it, but IMO much cleaner and easier to navigate.  I am currently running openSUSE, and the most annoying part was changing the system-wide/log-in layout.  It's somewhere in YaST where you'd expect it, but not exactly easy to find.

I have PC-BSD installed also, and because it uses KDE by default its per-user keyboard layout setup is the same as openSUSE, but I was unable to get the login screen layout changed from QWERTY at all in the time I tried.

In every single one of these operating systems, there is no way to switch the keyboard layout directly on the log-in screen.  While this can be viewed as a "feature" to keep people off your computer and is not needed for anyone who only uses one layout (ie. the QWERTY masses), it should at least be possible to easily set up if needed.

True. Sadly true...

I switch back and forth two layouts when I write document in Korean: Sebul for Korean, Colemak for English.  It takes more time and energy to have equal speed and accuracy of multiple layouts.

My typing speed for Korean is about 40 wpm, English in Colemak is average 70 wpm in normal pace. I like where I am at.

I lost touch typing skill of Qwerty since I became full-time Colemak user. Good thing is I can type slowly on other people's computers seeing keys. Others can't type on my computer.  My keyboard's key caps are Qwerty layout.

I use Debian Linux. I had to do extra work for making Colemak as default layout. I totally agree about layout selection feature during login. It will remove the complication of mixing multiple layout in computer.

I, btw, sometimes make passwords that make sense on one layout, but written on another: like "password" typed on Qwerty, pressing the Colemak keys → "raddw;sg". True, you might have to learn to type it differently on different layouts, but that's one way to take multiple layouts skills to practice.

Just saying, maybe it'll give someone ideas.

I use a Kineses keyboard for colemak at work, and standard qwerty keyboards and laptops everywhere else, so it feels very different. I think having different keyboards uses different muscle memory for each layout. I don't notice ANY conflict or decrease in my qwerty speed, at all.

I can confirm that I can switch layouts at the login screen under Windows 8 (with no registry hacks). *

For those that don't get the need to switch layout at login, you don't grok accessibility.

As I've said before, Tony's password hack is just that: a hack.

Don't any of you share your computers?

* Update

You don't get presented with an alternative layout at login, until you setup the layout under the user account.

On our Windows 8 machine, I have Qwerty and Dvorak setup, with Qwerty as the default layout.  It's a shared PC.  We could use multiple user accounts (and this works quite nicely too under Windows 8), but we don't as it gets cumbersome adding and configuring multiple accounts across PCs: setting up layouts, setting up browser plugins etc.

To switch layouts, I use Windows + Space (which is what I was used to under OSX), and Windows now lets you switch to your alternative layout globally across application windows (in the past the secondary layout would be window/application specific (and I even had an issue where I had to switch the layout multiple times within Internet Explorer one day!)  Switching to another application might need another layout switch.  Your brain can end up in knots. I can understand the need for having different layouts in different windows/applications: you might have your native browser selected in a web browser, with a foreign language selected in say a word processor. 

I do have to switch layout at the login screen, and then switch layout once I've logged in (yawn).  That's slightly cumbersome - but it's somewhat of an improvement!  (I really should setup automatic login...)

My keyboard switching tray app sometimes corrupts under Linux/Debian/Xfce, which is pretty rotten.  I used to be able to say to the lady friend, just hit such and such shortcut to switch.  I don't wish to confuse her.  In fact I try my best to just use Dvorak without really alerting anyone to it if I can.  Having a visual notifier/reminder of your layout is very useful for the times you have got an alternative selected.

To cut a long story short: switching and setting up alternative layouts under different OSs is not always easy or intuitive (it's a mine field).  That's enough to put you off of trying an alternative layout and/or letting go of Qwerty.

I don't see why you couldn't have a pool of layouts available at login time, the layout definitions can't be that large.

It's quite possible that the reason I have no problem switching between Colemak and QWERTY is that I'm not touch typing the latter. That is, I touch type Colemak on the kinesis, whereas I type ad hoc on standard keyboards.