Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
prif-
→
Welsh
prifathro
(affix)
→
Welsh
prifathrawes
(affix)
→
Welsh
prifair
(affix)
→
Welsh
prifgost
(affix)
→
Welsh
priflythyren
(affix)
→
Welsh
prifwynt
(affix)
→
Welsh
prifardd
(affix)
→
Welsh
prifodl
(affix)
→
Irish
príomh-
(cognate)