Form Anglois Culture should turn the Welsh and Cornish into Bretons or another Brythonic culture within the French group eg something like Brythonois

[King Ryan]

I don't think the English becoming culturally closer to the French would magically make the Brythonic Celts (Welsh and Cornish) lose their identity and it just so happens that there is already a Brythonic culture (Breton) within the French culture group; conceivably they would interact with each other both within the Angevin realm

 

[Oporto]

I'd rather see Welsh, Cornish and Breton moved into Celtic culture group. Currently Celtic has only 2 cultures: Irish and Highlander.