change user interface language

[Thomas Blasejewicz]

Good evening
I am trying to switch the UI language, but don't have much success.
The official documentation says:

"https://help.ubuntu.com/community/SwitchingLanguages
SwitchingLanguages
.................
To change the language of your next session, you will need to change it
from the login screen.
Before logging in, click on Options (found in the bottom left corner of
the login screen)
> Select Language and choose the language for your next session.
The system will ask you if you would like to change the language of the
login screen as well,
and whether the change is only for one session or permanent. After this,
you may log into your account."

On MY login screen there is no such item as "Options".
I DO have English, German and Japanese installed
In the menu "System settings -> language support" English appears first,
but all other items are greyed out => I cannot choose them.
-> But I am supposed to be able to.

Can someone please point me to the trick necessary to achieve this?
Thank you.