Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
know
←
Proto-Brythonic
*know
(inherited)
←
Proto-Celtic
*knūs
(inherited)
→
Cornish
knowen
(affix)