The author uses the theologian and university chancellor Jean Gerson (1363-1429) as a case study to examine how teenage boys in medieval Europe managed to adapt to the learned Latin culture of the university milieu, especially at Paris. Because Gerson wrote the same treatises in both Latin and French, we can discover how Gerson expressed similar ideas in the two languages. Thanks to the work of Ouy, we can see a "Gerson bilingue", which enables us to experience how Latin scholastic culture in the late Middle Ages came to convey its pastoral theology in the vernacular. In this process arose a new practice of translation from Latin to French.