iPhone address book

Can’t you not go to Settings>Language & Region and alter the “Region” section to your liking.

It's under Settings>General>... scroll down to Language & Region.

Regards

Giulio

This is Apple's help article re changing device language.

Change the language on your iPhone, iPad, or iPod touch - Apple Support

I was under the impression when changing Region it selects the appropriate Language by default, but you may have to change that manually as well under certain conditions.

Really not sure now, the only reason I suggested checking the iPhone Language was because you said making changes under Region made difference.

After altering the two above sections to your desired setting, have you tried restarting the device. Then go back in and see if they have stayed the same, following that open Contacts (Address Book) and see what happens.

I’m not aware of any other areas within iOS that would alter those settings, someone else might though.

Yes, missed out "General" after "Settings", sorry about that. More importantly did it work?

ps. Just missed your last post, what do you have at the top under iPhone Language, and can you change it.