Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*eni
→
Breton
e
(inherited)
→
Welsh
yn
(inherited)
→
Irish
i
(inherited)
→
Middle Welsh
yn
(inherited)