Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Indo-European
[[*-eh₂kos]], [[*-eh₂ḱos]]
→
English
Kelleher
(derived)
→
Scottish Gaelic
-ach
(inherited)
→
Manx
-agh
(inherited)