The Continental Celtic languages are the now-extinct group of the Celtic languages that were spoken on the continent of Europe and in central Anatolia, as distinguished from the Insular Celtic languages of the British Isles and Brittany. Continental Celtic is a geographic, rather than linguistic, grouping of the ancient Celtic languages. These languages were spoken by the people known to Roman and Greek writers as the Keltoi, Celtae, Galli, and Galatae. They were spoken in an area arcing from the northern half of Iberia in the west to north of Belgium, and east to the Carpathian basin and the Balkans as Noric, and in inner Anatolia (modern day Turkey) as Galatian. Even though Breton has been spoken in Continental Europe since at least the 6th century AD, it is not considered one of the Continental Celtic languages, as it is a Brittonic language, like Cornish and Welsh. A Gaulish substratum in Breton has been suggested, but that is debated.

Attested languages

It is likely that Celts spoke dozens of different languages and dialects across Europe in pre-Roman times, but only a small number are attested:

Use of term

The modern term Continental Celtic is used in contrast to Insular Celtic. However, while many researchers agree with the Insular Celtic hypothesis that the Insular Celtic languages constitute a linguistically distinct branch of Celtic (Cowgill 1975; McCone 1991, 1992; Schrijver 1995) that has undergone common linguistic innovations, there is no evidence that the Continental Celtic languages can be similarly grouped. Instead, the group called Continental Celtic is paraphyletic; the term refers simply to non-Insular Celtic languages and not to any special linguistic relationship between them as a group other than they are Celtic. Since little material has been preserved of any of the Continental Celtic languages, historical linguistic analysis based on the comparative method is difficult to perform. Meanwhile, under the P/Q hypothesis, other researchers see the Brittonic languages and Gaulish as forming part of a subgroup of the Celtic languages that is known as P-Celtic. Under this hypothesis, Continental languages are P-Celtic except for Celtiberian and Gallaecian, which are Q-Celtic. The Continental Celtic languages have had a definite influence on all of the Romance languages.