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

→ Cimbrian er (inherited)
→ Cimbrian èar (inherited)
→ German er (inherited)
→ Mòcheno er (inherited)
→ Old Frisian -er (inherited)
→ Saterland Frisian er (inherited)
→ Yiddish ער (inherited)