Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
parth
←
Proto-Brythonic
*parθ
(inherited)
←
Latin
pars
(derived)
→
Cornish
a-barth
(compound)
→
Cornish
kledhbarth
(compound)
→
Cornish
dyghowbarth
(compound)
→
Cornish
parthow
(suffix)