These languages were spoken by the people known to Roman and Greek writers as the Keltoi, Celtae, Galli, and Galatae.

[citation needed] 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.

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: The modern term Continental Celtic is used in contrast to Insular 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.

[4] Under this hypothesis, Continental languages are P-Celtic except for Celtiberian and Gallaecian, which are Q-Celtic.