Where was Old French language spoken?

Old French (franceis, françois, romanz; Modern French: ancien français) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligible yet diverse, spoken in the northern half of France. These dialects came to be collectively known as the langue d'oïl, contrasting with the langue d'oc in the south of France. The mid-14th century witnessed the emergence of Middle French, the language of the French Renaissance in the Île de France region; this dialect was a predecessor to Modern French. Other dialects of Old French evolved themselves into modern forms (Poitevin-Saintongeais, Gallo, Norman, Picard, Walloon, etc.), each with its own linguistic features and history.

Northern half of France in the 8th to 14th centuries.