See here for the translated rom for all xiaomi devices. This isn't a package that include italian translations, it's a full rom. It's impossible to make only an app for translations.
1) You don't need root permissions
2) You won't get official updates from xiaomi but unofficial updates from...
Stable china is a rom, dev china is another rom. What rom do you want?
You need to unlock your bootloader. For now you can't
~ Xiaomi Redmi Note 2 Prime ~
Do you know there aren't only Polish and English person in Europe? If it's the last hope for Mi2 the Mi2 is completely dead...
~ Xiaomi Redmi Note 2 Prime ~
Here you can find the official miui fastboot rom downloads. If you want another fastboot rom you have to ask to the makers of that rom.
I have never seen a fastboot rom that isn't official
~ Xiaomi Redmi Note 2 Prime ~
Xiaomi 4 isn't a device... Maybe Xiaomi Mi4?
Here you can find all the fastboot roms. Your should be the Xiaomi Mi 4 CDMA/WCDMA/LTE Latest Global Developer Version Fastboot File Download
~ Xiaomi Redmi Note 2 Prime ~