Southwestern Brittonic languages

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 they gradually evolved into the Cornish and Breton languages. Both languages evolved from the Common Brittonic formerly spoken across most of Britain and were thus related to the Welsh and Cumbric varieties spoken in Wales and Hen Ogledd (the Old North. That is, Northern England and the Scottish Lowlands), respectively.

Southwestern Brittonic
Cornwall, Brittany
Linguistic classificationIndo-European
Proto-languageProto-Southwestern Brittonic

The earliest stage of the languages, Primitive Cornish/Primitive Breton, is unattested. Written sources are extant from the Old Cornish/Breton period, roughly 800–1100, in which phase the languages are indistinguishable. As such, some linguists such as Peter Schrijver suggest that the terms "Old Cornish" and "Old Breton" are geographical rather than linguistic, only describing whether a text was written in Cornwall or Brittany[citation needed].


Some of the sound changes that distinguish Southwestern Brythonic from Welsh include:

  • the raising of */(ɡ)wo-/ to /(ɡ)wu-/ in a pretonic syllable (in Welsh there was no raising)
  • the fronting of */aː/ to /œː/ (in Welsh it diphthongized to /aw/)
  • the fronting of */a/ to */e/ before */iː/ or */j/ in an old final syllable (in Welsh it diphthongized to /ei/)

Other significant differences are found in Welsh innovations in which Southwestern Brythonic did not participate, such as the development of the voiceless alveolar lateral fricative /ɬ/.[citation needed]


  1. ^ Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "Southwestern Brythonic". Glottolog 3.0. Jena, Germany: Max Planck Institute for the Science of Human History.