The special characters on Colemak resides, as you very well might know, on the same positions as on the US QWERTY. If you find that sufficient (like I do), programming should be no problem.

About internationalisation: depens on how much and how formally you need to type in them. I suppose both Spanish and French looks similar enough to English to be feasible. In fact, from my own French typing experience, that is kind of comfortable, except for when you have to reach for Q. But it can't be worse than QWERTY.

Spanish (after some test copying a wikipedia article) seems possible too. The downsides of Spanish on Colemak seems to be all the accents, as áéíóú are accessable with alt gr + letter, and ñ through alt gr + n.

If you can cope with that, I'd suppose it's worth a try at least.

(And I'm sorry if my post is all messed up, I'm in kind of a hurry and got too little sleep.)

How convenient, I too type in Spanish, English and French. I find that mostly Colemak is definitely better than the alternatives for international typing too. Spanish works mostly except for reaching for q which is more often and same finger increases thanks to the popularity of the ue combination. It is also more common in French. What is nice, unlike Dvorak is that h is not messing everything up. It's also very nice to have finger rolls in French in Colemak. As in Spanish. Writing bien is amazing in Colemak. Just putting that out there. Colemak is very convenient really. It may not be optimized for it, but it definitely works and I don't feel the need to learn more than one layout (Colemak, excluding QWERTY of course which I still have to use sometimes).

I don't do any programming so I don't know how inconvenient Colemak would be for Bash and Perl.

Warning: In the first few paragraphs I talk about Programmer Dvorak, not Colemak.

I find that I really don't care much for the special characters used in programming. If they are in the same place we find them on a standard US layout, that's pretty much OK for me. With Programmer Dvorak I find myself doing lots of combinations of Compose and other two keys. I mapped Compose to be the 102nd key.

For accents in Spanish isn't that bad, except that it relies heavily on the left pinky finger, because the accent key happens to be the one exactly next to 102. For ñ is very awful, since I have to do compose, then Shift+~ (the key just under Esc), and then n. That takes 4 keystrokes, although I don't have to do single-hand combinations, which makes is still nicer than typing it with the Swiss layout.

For some French accents, it's just as bad as ñ, for example, both grave accent (`) and circumflex (^) are to the very far edge of the keyboard, and only accessible through Shift combinations.

Dvorak interational seems to be at least as bad a Programmer Dvorak. I don't get why they have qualified it of international, since you can't type fast Spanish on it, which happens to be the second most used language of the western world, and the third on the planet.

Now I will talk about Colemak:

For these keys I see Colemak has a nice combination of AltGr plus some key at the left of the keyboard. For ç I can use AltGr+C. For acute I go for AltGr+T, then the character I want to accentuate. for grave it's the same but with AltGr+R instead of T. For ñ it's just as bad as Programmer Dvorak, and for circumflex it's almost as good as for grave and acute.

These combinations seem much better than the Programmer Dvorak ones, which use a Compose key. But I'm not quite convinced yet that it represents any improvement over the localized QWERTY/QUERTZ/AZERTY versions for Spanish and French. That's exactly what I want to know from someone with experience with standard Colemak and who types regularly on any of those languages.

That's very true, but I didn't mention it because it's located at the right of the keyboard. AltGr is to the right of the keyboard, and it doesn't play well with keys at the same side because I can't keep both hands on their natural typing positions to type the combination.

I use the medium finger to press it when typing normally, and the thumb when using same-hand combinations.

As I've played piano, I don't find the thumb-to-altgr-stretch hard to do at all, and it works well with ñéíó and ú. Á too, of course, but that's not a same hand combination.

Have you tried using LeftCtrl+RightAlt? It should work in most cases I think, but I haven't tried any ANSI boards myself.

I use mostly PKL to impement layouts these days, and you can fairly simply get what you want there. I use a Compose-alike setup where the ' key does acute accent, `+~^ their respective accents, comma cedilla and colon diaeresis (all as dead keys). Wouldn't be too hard to make a setup like that for MSKLC so it could be installed as a normal Windows layout either. If you use any other OS, it's mostly just a matter of editing a file too (but I'm not so well versed with those).

Another way is to simply make an AutoHotKey script - search the AutoHotKey help files.