Going from Kurdish to Yiddish (ייִדיש) has a composite linguistic distance of 70% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Latin/Arabic → Hebrew
Indo-European ↔ Indo-European
The 5 languages with the lowest linguistic distance from Kurdish:
A quick 3-question check between Kurdish and Yiddish. No signup.