Note 17 — Chapter III · Fairy Ways and Words (continued 2)
Reading edition
This is pronounced Rhiwan, though probably made up of Rhiw-wen, for it is the tendency of the Gwyndodeg to convert e and ai of the unaccented ultima into a, and so with e in Glamorgan; see such instances as Cornwan and casag, p. 29 above. It is possibly a tendency inherited from Goidelic, as Irish is found to proceed in the same way. ↑