Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
gouel
←
Welsh
gŵyl
(cognate)
←
Welsh
hwyl
(cognate)
←
Cornish
gool
(cognate)
←
Latin
vigilia
(derived)
→
Welsh
hwyl
(cognate)