How can I uninstall a language?

I changed my site language a few times for testing purposes. The problem is that after changing it back, WordPress continues to update plugin language packs. How can I uninstall those languages that got installed when I selected them as the Site Language for testing? If I select the Site Language dropdown, I can still see them under “Installed”.

What are nulled themes?

In WordPress there is a concept of “Nulled Themes”. I searched information about it (on Google) and found some people say it is hacked and others say it is not. I ran the “iThemes Security” software over it and everything works without errors.