Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
Gouezel
←
Old English
wāþ
(cognate)
←
Proto-Brythonic
*guɨðel
(inherited)
←
Proto-Celtic
*wēdus
(derived)
←
Welsh
Gwyddel
(cognate)
←
Proto-Indo-European
*weydʰ-
(derived)
→
Breton
gouezeleg
(suffix)
→
Welsh
Gwyddel
(cognate)