I have heard a few times the devs mention that hearthlings will independently do things when not assigned to a task, like dance or go to festivals. I think chatting to each other in a visual way, like with speech bubbles, would be cool. I have attached screenshots from Spore and Sims to show what I mean. Sometimes they just talk about random glyphs that allow us, the watcher, to develop our own stories (which I like), and sometimes they will talk about things in recent memory (their partner being promoted, work, woohoo).
It would be cool to see hearthlings “discussing” goblins, berries, tools etc on their “down” time.