How to change system language?

Solution 1:

Obviously the language support tools are still incomplete in Ubuntu GNOME. Desktop Help states the following:

Select your desired language. If your language is not listed click : at the bottom of the list to select from all available regions or languages.

Only after selecting a language there clicking on Done has no effect.

To have the language selection back in the form it is installed in other releases we have to install language-selector-gnome . After we did so, we will have an additional icon "Language Support" in our System Settings from where we can install any supported language by choosing "Install/Remove Languages":

Drag the interesting language to the top of the list. Select "Apply System Wide" to also have this language at log in, and system wide.

Solution 2:

If I understand the question right, you want to change everything to polish. If that's the case then, add the language first, and Apply system wide.

Do the same for Regional Format

And add the keyboard layout.

Then you will get the language icon which allows you to switch between keyboard layouts.

Solution 3:

Specify the language at the login prompt after selecting the user. When asked whether to make the selection the new default, select yes