I have setup support for multiple languages in my application. I have localized the form, set all labels and also built my resX files holding the translated messages. This all works fine while running it in debug mode from within Visual Studio, but when I run the "Release" version outside of Visual Studio, it will not change the language.
My main question is: Is this happening because I don't have that specific language installed on my system? Will it change language for someone who has Windows installed in that language still? Or if they have that language installed?
When you run your application in release, you mean starting the .exe? If so, please validate that the directory you are in have the folder of each language.
For example, if your application is by default in english and that you offer french support, you should have a folder called "fr" which contains the ressource dll for your application.
If you don't, I think it will default to the base language of your application.