Celtic languages are the languages descended from Proto-Celtic, both those spoken by the ancient Celts, and those used by their modern descendants, the Gaels, Welsh, Cornish and Bretons. They are a branch of the Indo-European language family. They were spoken across western Europe during the 1st millennium BC, but are now limited to a few enclaves in the British Isles and on the peninsula of Brittany in France.
There are four main groups of Celtic languages, of which the first two are now long extinct:
Gaulish and its close relatives, Lepontic and Galatian. …