how to change language?

I have installed Gnome 3 on FreeBSD 11.0. No matter what I try, it is still English.

I have edited .login_conf:

german|German accounts:\

and changed the language to German within Gnome, still no luck.
Hmm, this does not look like my Gnome 3 settings panel. And as I have said, I already have switched the language in Gnome, but it is still English.
Did you run cap_mkdb /etc/login.conf?

Run the above command and make sure a ~/login_conf.db file appears.

Take a look to login.conf(5) manpage for further details.
And are you in the "german" login group?
If you use gdm as display manager, then you have to edit /usr/local/etc/gdm/locale.conf and replace all occurrences of "en_US" with "de_DE". (Restart your session).