History of French

French is a Romance language (meaning that it is descended primarily from Vulgar Latin) that specifically is classified under the Gallo-Romance languages.

The discussion of the history of a language is typically divided into "external history", describing the ethnic, political, social, technological, and other changes that affected the languages, and "internal history", describing the phonological and grammatical changes undergone by the language itself.

Before the Roman conquest of what is now France by Julius Caesar (58–52 BC), much of present France was inhabited by Celtic-speaking people referred to by the Romans as Gauls and Belgae. Southern France was also home to a number of other remnant linguistic and ethnic groups including Iberians along the eastern part of the Pyrenees and western Mediterranean coast, the remnant Ligures on the eastern Mediterranean coast and in the alpine areas, Greek colonials in places such as Marseille and Antibes, and Vascones and Aquitani (Proto-Basques) in much of the southwest. The Gaulish-speaking population is held to have continued speaking Gaulish even as considerable Romanisation of the local material culture occurred, with Gaulish and Latin coexisting for centuries under Roman rule and the last attestation of Gaulish to be deemed credible having been written in the second half of the 6th century about the destruction of a pagan shrine in Auvergne.

The Celtic population of Gaul had spoken Gaulish, which is moderately well attested and appears to have wide dialectal variation including one distinctive variety, Lepontic. The French language evolved from Vulgar Latin (a Latinised popular Italic dialect called sermo vulgaris), but it was strongly influenced by Gaulish in its grammar. Examples include sandhi phenomena (liaison, resyllabification, lenition), the loss of unstressed syllables and the vowel system (such as raising /u/, /o/ → /y/, /u/, fronting stressed /a/ → /e/, /ɔ/ → /ø/ or /œ/). Syntactic oddities attributable to Gaulish include the intensive prefix ro- ~ re- (cited in the Vienna glossary, 5th century) (cf. luire "to glimmer" vs. reluire "to shine"; related to Irish ro- and Welsh rhy- "very"), emphatic structures, prepositional periphrastic phrases to render verbal aspect and the semantic development of oui "yes", aveugle "blind".

Some sound changes are attested: /ps/ → /xs/ and /pt/ → /xt/ appears in a pottery inscription from la Graufesenque (1st century) in which the word paraxsidi is written for paropsides. Similarly, the development -cs- → /xs/ → /is/ and -ct- → /xt/ → /it/, the latter being common to much of Western Romance languages, also appears in inscriptions: Divicta ~ Divixta, Rectugenus ~ Rextugenus ~ Reitugenus, and is present in Welsh, e.g. *seχtan → saith "seven", *eχtamos → eithaf "extreme". For Romance, compare:

Both changes sometimes had a cumulative effect in French: Latin capsa → *kaχsa → caisse (vs. Italian cassa, Spanish caja) or captīvus → *kaχtivus → Occitan caitiu, OFr chaitif (mod. chétif "wretched, feeble", cf. Welsh caeth "bondman, slave", vs. Italian cattivo, Spanish cautivo).

In French and the adjoining folk dialects and closely related languages, some 200 words of Gaulish origin have been retained, most of which pertaining to folk life. They include:

Other Celtic words were not borrowed directly but brought in through Latin, some of which had become common in Latin, braies "knee-length pants", chainse "tunic", char "dray, wagon", daim "roe deer", étain "tin", glaive "broad sword", manteau "coat", vassal "serf, knave". Latin quickly took hold among the urban aristocracy for mercantile, official and educational reasons but did not prevail in the countryside until some four or five centuries later since Latin was of little or no social value to the landed gentry and peasantry. This eventual spread of Latin can be attributed to social factors in the Late Empire such as the movement from urban-focused power to village-centred economies and legal serfdom.