French is a Romance language of the Indo-European family. Like all other Romance languages, French and its closest relatives—the langues d'oïl, historically spoken in northern France and southern Belgium—descended from the Vulgar Latin of the Roman Empire. It was influenced by native Celtic languages of Northern Roman Gaul and by the Germanic Frankish language of the post-Roman Frankish invaders. Over time, French largely supplanted most regional Romance varieties across France, Belgium and Switzerland. As a result of French and later Belgian colonialism, it was introduced to new territories in the Americas, Africa, and Asia, and numerous French-based creole languages, most notably Haitian Creole, were developed. A French-speaking person or nation may be referred to as Francophone in both English and French.