Proto-Germanic *þurbaną

→ English thair (derived)

→ Old English þurfan (inherited)

→ German dürfen (inherited)

→ German turde (inherited(de/da))

→ Middle English tharf (mention)

→ Middle English tharen (inherited)

→ Old Swedish þorva (inherited)

→ Central Franconian dürve (inherited)

→ Gothic 𐌸𐌰𐌿𐍂𐌱𐌰𐌽 (inherited)

→ Alemannic German törfe (inherited)

→ Icelandic þurfa (inherited)

→ Luxembourgish däerfen (inherited)

→ Dutch durven (inherited)

→ Old Norse þurfa (inherited)

→ Old Norse þurft (suffix)

→ Old Dutch thurvan (inherited)

→ Old Saxon thurvan (inherited)

→ Yiddish דאַרפֿן (inherited)