One of two major divisions of modern-day Celtic languages (the other being Goidelic). Also known as P-Celtic, for the way it uses a "P" to begin words that, in the hypothetical base Indo-European language, began with "Qu".
The main living Brythonic languages are Breton and Welsh; other notable tongues are Cornish (which has no native speakers, but is being resurrected), and perhaps the extinct Pictish (though records of Pictish are not extensive enough to be sure). Once Brythonic languages encompassed all of Britain (though not Ireland), but they were driven to the fringes of that island by the invasions of the Angles, Saxons, and Jutes which brought English to Britain. Brythonic languages then disappeared from Scotland after Irish colonists brought a Goidelic language with them from their home island.