Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*tū
→
Breton
te
(inherited)
→
Gaulish
tu
(inherited)
→
Welsh
ti
(inherited)
→
Irish
tú
(inherited)
→
Manx
oo
(inherited)
→
Old Irish
tú
(inherited)