Using the locale / contry setting provided by OS should be good enough for 1.0. After 1.0 is out there could be an user setting for overriding the OS locale information for teletext. So feel free to provide a patch that fixes the language issue all nor/swe/fin/dan users are facing today in teletext & teletext subtitles.
I have changed the code so that these special characters only goes into effect if the setting in the attached picture is danish.
I also saw that someone had tried to translate danish characters in teletext subtitles before, but maybe missed the 2 capital letters - I added these and reverted the character table changes.
But take a look at the diff files, it is very minute changes.
I haven't done anything for Norway because there seems to be several Norwedian languages - and I don't know how they would like this changed.