Hmm, good to see that this is possible but I wouldn't exactly call that a "quick way". Compare it to Windows' Alt+Shift to shuffle through keyboard layouts and the RISC OS way becomes awful and the *country method is a horrible hack to say the least. But still, this is something I had missed and you two are the first I've "met" that seem to have known about it. I did in fact RTFM many years ago but didn't come across this.
It's good that ROL have put the link to a4com to their site but that doesn't change the fact that we're still relying on a third party module that may or may not be available. Why not add the support to the OS itself?
As for "most commercial OSs", with Windows you usually don't have to pay anything extra to get the localised version, it costs the same and even the English version includes support for all the internationalisation issues that I have mentioned. MacOS is a different story in that (at least in Iceland) you get the Icelandic translation/localisation but if you buy your Mac outside Iceland you have to pay somewhere in the region of £100 to get the Icelandic keyboard and even that doesn't seem to work well. At least RISC OS scores better than MacOS in that area but still lags way behind Windows and Linux.
RISC OSs method of offering translations is an excellent way for the most part (editing Template files isn't a smart thing to do in my opinion). I took part in translating RISC OS 3.1 and 3.5 to Icelandic a while back so I truly appreciate the way it works. Now only if RISC OS where to use layout managers to create its windows this could truly work well, some of the translations had to be less than good just to fit the text into the available space.