Most humans were illiterate and had a small vocabulary consistently of only a tiny portion of their languages actual vocabulary. The modern world with its high literacy rates is exceptional. As a direct result many words have completely lost their meaning and in some cases even taken on opposite meaning to their original intention!
I believe this a direct result of people fighting to be accepted by the small elite that could read. Write a paper in the 1700’s using the phrase “literally famished” to mean you haven't eaten since lunch and you would be laughed out of the building. Write it now on Twitter and no one in your in group is going to call you out because they know what you mean and ‘sanctity’ of the language is much less important to them then social cohesiveness, if they even care at all.
