Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
trech
←
Breton
trec'h
(cognate)
←
Proto-Brythonic
*trex
(inherited)
←
Proto-Celtic
*trexsos
(inherited)
←
Cornish
trech
(cognate)
←
Old Irish
tressa
(cognate)
→
Welsh
trechu
(affix)
→
Welsh
trechedd
(affix)