Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
pednseythen
←
Cornish
penn
(prefix)
←
Cornish
seythen
(prefix)
→
Cornish
pednseythednow
(suffix)