Examples: cartography card archaeology archetype monarchy legal loyal purse personal cinema kinase car carpenter hippopotamus Mesopotamia dative data date
...
Old Irish -acht
← Proto-Celtic *-axtā (derived)
← Proto-Celtic *axtā (inherited)

→ Irish -acht (inherited)
→ Scottish Gaelic -achd (inherited)
→ Manx -aght (inherited)
→ Old Irish Connachta (affix)
→ Old Irish deacht (affix)
→ Old Irish muccaidecht (affix)
→ Old Irish bendacht (affix)
→ Old Irish dóenacht (affix)