What if they communicated via iconography only? What if they ask each other for help in this way?
e.g. “Hey, I’m tired. Would you help haul crops from the farm so I can rest for a while?”
This might be represented by a slumping gait, a wiping of the brow followed by a speech bubble containing a bed. The hearthling wanders past someone who just finished a job but is otherwise okay to work, so you see a new speech bubble that shows the other hearthling’s portrait and an icon of a food basket followed by a question mark. The other hearthling looks at the tired hearthling, throws them a big thumbs up and sets off for the farm.
The AI implications here are that a hearthling can transfer a task it currently has assigned to it, when its basic needs are nearing their low thresholds. Players could even be granted the ability to define through the UI which hearthlings are able to do favors for others. A favor would be defined as a task it normally isn’t permitted to perform, but for overflow purposes, it will perform upon specific request.
Example: I don’t want my blacksmith to haul normally. But if a huge chunk of mining just completed and there’s suddenly a huge uptick in hauling, the normal haulers would still handle it themselves until one of them burns out from exhaustion and asks for help. Only then might the blacksmith jump in to lend a hand. And, when they do, using the above speech bubble interaction, we the players get to witness it.
Such a system would even allow for fun little touches like granting an XP bonus to hearthlings that complete tasks that were transferred to them, as a reward for being a team player. 