'The Fairies' is a short story from Charles Perrault's Fairytales where a beautiful but put-upon young girl is kind to a stranger who, naturally, turns out to be a fairy and bewitches the girl so that jewels and pearls come from her mouth with every word she speaks. The moral is basically that when kind words are spoken; good things will come.
This is my imagining of the situation. You may get richer the more you talk, but it would be pretty gross to drool jewels. It's still a good reminder that you have the power to be cruel or kind with your words.