In the story "The Mouse and the Motorcycle" by Beverly Cleary, it is explained that both the mouse and the boy understand each other effortlessly. Their shared passion for motorcycles creates an instant connection, allowing them to communicate as if they spoke the same language. This mutual understanding highlights the bond formed through their common interests.
Neither the mouse nor the boy was the least bit surprised that each could understand the other. Two creatures who shared a love for motorcycles naturally spoke the same language.