Changing the language in Gimp 2.8.6 when entries are missing from the language drop-down
I installed Gimp 2.8.6 on a Windows 7 machine where the language of the operating system was English. I made sure that the translations were also installed, but, strangely, when I started Gimp, only "System language" and English were available in the language drop-down in the preferences window. I couldn't find anything by searching for this particular problem, and all the other suggestions about changing the language of Gimp like adding a LANG environment variable or deleting all locales except the desired one failed.
After reading almost all configuration files, fortunately I found [SYSTEM_DRIVE]:/Users/[USER_NAME]/.gimp-2.8/gimprc, which already had a line in it setting the language to English. (You may need to toggle the language setting in the preferences before it appears.) Changing it manually to the name of the locale (take a look at the [SYSTEM_DRIVE]:/Program Files/GIMP 2/share/locale/ folder for the available ones) solved the problem (although the language drop-down still doesn't work).
After reading almost all configuration files, fortunately I found [SYSTEM_DRIVE]:/Users/[USER_NAME]/.gimp-2.8/gimprc, which already had a line in it setting the language to English. (You may need to toggle the language setting in the preferences before it appears.) Changing it manually to the name of the locale (take a look at the [SYSTEM_DRIVE]:/Program Files/GIMP 2/share/locale/ folder for the available ones) solved the problem (although the language drop-down still doesn't work).