...anyway, although the work has already been done from my side so there's no much point in writing what I'm about to:
I see the translation of province names as something (almost) useless. I mean, even if I play the game in Italian, I prefer to have the cities in English since that way they match their name on the actual map, and so it's easier to find one when I need to.
That is your choice and you can easily mod the province_names.csv file to your liking.
Unless, of course, the E3 map had different on map drawn names matching the language chosen in settings.cfg...
If you choose a different language in settings.cfg the game simply uses the column of this language in the province_names.csv file. The names on the map themselves can't be changed by editing the province_names.csv file. If you change the name of a province you'll see your change only then if you click onto this province to see the province stats.