Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
cy-
←
Welsh
cyf-
(mention)
←
Cornish
ke-
(cognate)
←
Cornish
ky-
(cognate)
→
Welsh
cysyniad
(affix)
→
Welsh
cyngerdd
(affix)
→
Welsh
cysgod
(prefix)
→
Welsh
cytref
(affix)
→
Welsh
crybwyll
(affix)
→
French
cohue
(cognate)