Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
laouen
←
Proto-Brythonic
*llowen
(inherited)
←
Proto-Celtic
*lowenos
(inherited)
←
Welsh
llawen
(cognate)
←
Cornish
lowen
(cognate)
←
Middle Breton
louen
(inherited)
→
Welsh
llawen
(cognate)
→
Cornish
lowen
(cognate)