Hi,
could you please provide us more details about your scenario. Where would you like to change your UI culture?
You said that you would like to set UI culture for anonymous users. But IU culture sets culture of
CMS Desk/Site manager where anonymous users have not access. You can set the default UI culture only for users already created in the system (Site Manager - Administration - Users - your_user - General - Preferred user interface culture).
Have you created and used your custom culture string according to this
tutorial?
Now in your scenario - there is a live site, anonymous user prefer for example French version therefore he changes the language in the language selector and the content of page is changed to French version except of your culture strings?
Where are you using these strings?
Best regards,
Ivana Tomanickova