Brittonic

Brittonic, also called Brythonic, is a branch of the Insular Celtic languages. It comprises the languages historically spoken in Great Britain and Brittany and forms the western branch of the Celtic family, alongside Goidelic (Gaelic). The term is used by linguists to describe Common Brittonic and its later descendants, distinguishing them from the Goidelic languages.

Brittonic languages descended from Proto-Celtic through Common Brittonic, spoken across much of Britain after the early Iron Age. From this ancestor emerged several languages, of which Welsh, Cornish, and Breton are the best known. Extinct varieties included Cumbric, once spoken in the Anglo-Celtic borderlands of northern England and southern Scotland, and possibly other regional Brythonic varieties such as Pictish, whose exact classification remains debated.

In the early medieval period, the Brittonic-speaking world fragmented: Welsh and Cornish remained in Britain, while speakers migrated to Brittany, giving rise to Breton. The three languages developed distinct literatures and dialects, with ongoing contact with Latin, Old French, and English. In the modern era, Welsh and Breton remain living languages with active communities; Cornish, after a period of decline, has seen revival efforts since the 20th century.

Historically, Brittonic languages share certain features with other Celtic languages, including flexible word order and initial consonant mutations. They are typically written with adaptations of the Latin alphabet. Welsh has a rich literary tradition, Breton maintains regional literature, and Cornish revival efforts have produced new publications and educational initiatives.