Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Manx
doo
←
Proto-Celtic
*dubus
(inherited)
←
Proto-Indo-European
*dʰewbʰ-
(root)
←
Proto-Indo-European
*dʰewbʰ-
(derived)
←
Old Irish
dub
(inherited)
→
Manx
Divlyn
(cognate)
→
Manx
breck-ghoo
(compound)