Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
derwydd
←
Proto-Celtic
*druwits
(inherited)
←
Welsh
derw
(cognate)
←
Welsh
dryw
(cognate)
←
Irish
draoi
(cognate)
←
Cornish
drewydh
(cognate)
→
Welsh
derwyddiaeth
(affix)
→
Welsh
archdderwydd
(affix)
→
Irish
draoi
(cognate)