There are sayings in many languages about the difficulty of changing long-established habits. In English, “You can’t teach an old dog new tricks.” In French, “Ce n’est pas à un vieux singe qu’on apprend à faire la grimace” (You can’t teach an old monkey how to pull a funny face). In Spanish, “El loro viejo no aprende a hablar” (An old parrot can’t learn to speak).