Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
nyth
←
Proto-Brythonic
*nɨθ
(inherited)
←
Proto-Celtic
*nisdos
(inherited)
←
Proto-Indo-European
*nisdós
(inherited)
→
Welsh
nythod
(affix)
→
Welsh
nythaid
(affix)
→
Welsh
nythu
(affix)
→
Welsh
nythfa
(affix)