Godfrey of Bouillon, a key figure in the First Crusade, spoke Old French as his primary language, which was common among the nobility in the regions of Northern France during the late 11th century. Additionally, he was likely familiar with Latin, the language of the church and scholarship of that time, as well as the local dialects of the regions he governed.
As a noble knight, Godfrey would have used Old French in his everyday interactions, especially among his peers and soldiers. The feudal system of the period necessitated a strong grasp of this language for governance and military leadership. Furthermore, being an influential leader in the Crusades, Godfrey likely interacted with diverse groups, including the Latin-speaking clergy and various other cultures, which would have required some level of multilingualism.