Nothing so erudite (or even at all erudite) to add here, but it did set me thinking about the difference in the way way we use these words in set phrases:
- take liberties
- freedom of speech
and how bizarre those would sound if the words were reversed.

Freedom somehow seems more reciprocal to me than liberty - one person can take a liberty whatever society thinks, but freedom of speech is a communal decision and you can't have it unless you let others have it too.
I wonder if I thought that before I read your post, or whether I am being led to it by your etymology, Mav?