Examples: cartography card archaeology archetype monarchy legal loyal purse personal cinema kinase car carpenter hippopotamus Mesopotamia dative data date
...
Proto-Celtic *matis

→ Breton mad (inherited)
→ Breton mat (inherited)
→ Welsh mad (inherited)
→ Basque maite (derived)
→ Irish maith (inherited)
→ Scottish Gaelic math (inherited)
→ Manx mie (inherited)
→ Old Irish math (mention)
→ Old Irish maith (inherited)