Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
celfydd
←
Proto-Brythonic
*kėlβ̃ɨð
(inherited)
←
Proto-Celtic
*kalmiyos
(inherited)
→
English
clever
(cognate)
→
Welsh
celfyddyd
(affix)