All evidences in novel and anime indicates that the nation of Sauville, the academy and the de Blois all speak French as their official language. In the novels, it is noted that her name is apparently usually a man's, as Avril initially does not believe Victorique is a female student when she is being discussed.
The majority of sources in the novel and anime genres indicate that Sauville, the academy, and de Blois predominantly use French as their official language. In the novels, it is noted that her name appears to be traditionally masculine, leading Avril to initially question Victorique's female status when she is being discussed.