Deleting localization files on your machine is typically fine, but as you’ve seen sometimes applications don’t like it.
Just make sure to back up first (which is what I advise everyone to do before making any deletion that you’re not 100% certain of). Once you do that, if you delete those files and they stay away, great.
But keeping those files off your machine? That’s not necessarily so easy. I’ll explain why.
Windows and its translations
As you probably already know, Windows supports multiple languages. You’ll find it in the local language of many different countries around the world.
That doesn’t necessarily mean that an application (like iTunes, for example) would appear in those language as well. You may have to adjust iTunes settings to display the application in another language. While Windows does support common techniques for doing so, many software companies choose to develop their own international or localized support, particularly if the application they’re providing is also available on platforms other than Windows.
As a result there’s some inconsistency in the way that applications support multiple languages. That’s why you may see multiple language files for different programs. That’s also why some files stay deleted and some applications might automatically reinstall those files if they notice that they’re missing.
How do I remove redundant language files?
You won’t find a general-purpose utility to handle this for you. If a program like iTunes automatically replaces the missing languages, I don’t know of a workaround. The same is true for just about any other application that decides that its language files are important.
My best recommendation is to make sure that you always use the custom or advanced installation when you install a program on your machine. If they’re going to be present, any options for installing (or not installing) the various languages available are probably in the setup.
If the setting is not there, then I really don’t know of an official, comprehensive way to remove these files.
But I have to ask: is making sure deleted language files stay deleted really worth your time? In the end, the amount of space that’s taken up by these folders tends to be pretty small. If space is an issue, there more effective approaches to take.