I have a machine with Gnome on Bullseye. I set both Language and the Formats to German and Germany respectively in the Region and Language section of Settings GUI. After I restart the session, everything is still in English. The value of Language and Format fields are shown as German but the environment is still in English. This is on a non-admin account, but I have access to root.

When I run locale at the terminal I get:

LANG=de_DE.UTF-8
LANGUAGE=en_US:en
Everyhting else is set to de_DE.UTF-8

LC_ALL is not set (set to nothing).

Also I notice that on the Login screen, the day is shown in German and months names in Calendar are in German, but most everything else (menus, options, messages, etc.) is in English.

try
https://wiki.debian.org/Locale#:~:te...2Fetc%2Flocale.

Note files that affect languages include /etc/profile.d/something and home .profile

so get root and try

Thanks for the reply. Already tried that.
Somebody suggested that I should edit /etc/default/locale.
I did that and it seemed to work, with the caveat that now my admin account also changed language to German.
Then as per suggestion on Debian wiki, I ran dpkg-reconfigure and set the default to None.
It just comments out the LANG line in /etc/default/locale.
I also set the relevant fields in the Region and Language section of the Settings GUI.
After logout and login the admin account remained German, while the account that I wished to turn to German is back in English.
Following the other suggestions on Debian wiki, I tried the ~/.dmrc solution which did not work.

I added the line
to /etc/profile, but this broke the system so that I could no longer login. I had to remove it. (also tried it without the colon at the beginning, same result)

Right now, the account I had tried to change to German is in English, whereas the account that was supposed to be in German is in English. The settings GUI shows the right values, but the desktop environment ignores them. I can only characterize this as a bug.

^ something is very wrong about that line.

I suspect that GNOME cuts through long-established standards and uses its own settings:
https://help.gnome.org/users/gnome-h...nguage.html.en

For all those who later come upon this thread. Here's the right way to do it:

Edit the ~/.profile (on the home directory of the user whose desktop environment must be switched to another language) and paste the following: (this sample is for German, adapt the RHS values for your desired language)

LANG=de_DE.UTF-8
LANGUAGE=de_DE:de
LC_CTYPE="de_DE.UTF-8"
LC_NUMERIC="de_DE.UTF-8"
LC_TIME="de_DE.UTF-8"
LC_COLLATE="de_DE.UTF-8"
LC_MONETARY="de_DE.UTF-8"
LC_MESSAGES="de_DE.UTF-8"
LC_PAPER="de_DE.UTF-8"
LC_NAME="de_DE.UTF-8"
LC_ADDRESS="de_DE.UTF-8"
LC_TELEPHONE="de_DE.UTF-8"
LC_MEASUREMENT="de_DE.UTF-8"
LC_IDENTIFICATION="de_DE.UTF-8"
LC_ALL=

And that's it.

^ I believe that that fixed it for you, and well done, but really there's something borked on a higher level. This sort of workaround shouldn't be required.