Celtic /e:/ → Welsh <wy>
Posted: Mon Jul 24, 2017 4:13 am
What was the motivation behind this rather unusual sound change? Was it similar to or related in any way to /ei/ → /oi/ in French?
I mean, it is clearly similar. Are you asking if the two changes are ultimately connected or just parallel developments?
In Breton, the parallels are even closer, with Proto-Brittonic *uɨ becoming <oue> or <oa>, e.g.:
*pē(n)sum > *puɨs > W. pwys, B pouez
*cēra(m) > *kuɨr > W cwyr, B. koar