The Southwestern Brittonic languages are the Brittonic Celtic tongues spoken in South West England and Brittany since the Early Middle Ages. During the period of their earliest attestation, the languages appear to be indistinguishable, but eventually they evolved into the Cornish and Breton languages. They evolved from the Common Brittonic formerly spoken across most of Britain and were thus related to the Welsh and Cumbric dialects spoken in Wales and Hen Ogledd (northern Britain), respectively.