got a mix of ~10% Norwegian, the rest English.
Yes, not many of the messages have been translated in the Norwegian language file https://github.com/geany/geany/blob/master/po/nn.po and the last person who did any was back in 2012, so any contributors would help. Or maybe all Norwegian programmers speak English and don't need it.
Would be great with the ability to set the LANG environment variable in user context from Geany GUI, with a warning that it might impact other programs.
As has been said on other threads on the subject, setting it from the Geany GUI is too late, all the libraries that depend on it have already been loaded and initialized, some libraries may allow it to be changed, but that is not required to be supported except for some that POSIX says must, so it has to be set before the program starts and can't be changed from the GUI.
There was a contribution on another thread for how to set it for the Windows startup shortcuts which will (IIUC I don't use windows) only apply to this program.