> I've been told the suffix -iawn or -ion was often added to personal
names to give the name of a district ('territory of x') for example
Cunedda's sons Ceretic, Abloyc, Etern, and Osmail are remembered
in Ceredigion, Aflogyon, Edeyrnion, and Osmeliaun.
That seems to be the case in Wales, but of course Lleuddun was supposedly
from what is now southern Scotland.
The Proto-Celtic root *aidu- apparently did not survive in Brittonic; if
it did, I think we would expect it to produce Welsh *oedd.
> So Luguaidonas > Lleuoeddon then? And there's no way that would
end up shortened to Lleuddun or something similar?
I highly doubt it. The cluster -euoedd- occurs in Welsh, for example in
deuoedd and deheuoedd.
- Chris Gwinn