Going from Polish to Belarusian (ะะตะปะฐัััะบะฐั) has a composite linguistic distance of 41% (curated lexical data). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Latin โ Cyrillic
Indo-European โ Indo-European
The 5 languages with the lowest linguistic distance from Polish:
A quick 3-question check between Polish and Belarusian. No signup.