Going from Hindi to Malayalam (เดฎเดฒเดฏเดพเดณเด) has a composite linguistic distance of 80% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Devanagari โ Malayalam
Indo-European โ Dravidian
The 5 languages with the lowest linguistic distance from Hindi:
A quick 3-question check between Hindi and Malayalam. No signup.