Going from Tamil to Hindi (เคนเคฟเคจเฅเคฆเฅ) has a composite linguistic distance of 81% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Tamil โ Devanagari
Dravidian โ Indo-European
The 5 languages with the lowest linguistic distance from Tamil:
A quick 3-question check between Tamil and Hindi. No signup.