French is descended from Vulgar Latin, the vernacular Latin (as distinguished from literary Latin) of the Roman Empire (see Latin language). When ancient Gaul (now modern France) was conquered by the Romans in the 2d and 1st cent. B.C., its inhabitants spoke Gaulish, a Celtic language, which was rapidly supplanted by the Latin of the Roman overlords. In the 5th cent. A.D. the Franks, a group of Germanic tribes, began their invasion of Gaul, but they too were Romanized. Although modern French thus inherited several hundred words of Celtic origin and several hundred more from Germanic, it owes its structure and the greater part of its vocabulary to Latin.
By the 9th cent. the language spoken in what is now France was sufficiently different from Latin to be a distinct language. It is called Old French and was current from the 9th to the 13th cent. The earliest extant text in Old French is the Oaths of Strasbourg, dated 842. Of the various dialects of Old French, Francien (the north-central dialect spoken in Paris and the region around it) in time became the standard form of the language because of the increasing political and cultural importance of Paris. French from the 14th through the 16th cent. is known as Middle French. During this period many words and expressions were borrowed from Latin, Greek, and Italian, and a group of French poets, the Pléiade (see under Pleiad), encouraged the French to develop and improve their language and literature.
The modern period of French began in the 17th cent. In 1635 the French Academy was founded by Cardinal Richelieu to maintain the purity of the language and its literature and to serve as the ultimate judge of approved usage. While the vocabulary and style of Modern French have been influenced by movements such as romanticism and realism, structurally French has changed comparatively little since the Middle French period. Standardization of the French language has been aided in modern times by more widespread education and by the mass media.