Going from Tibetan to Zulu (isiZulu) has a composite linguistic distance of 77% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Tibetan β Latin
Sino-Tibetan β Niger-Congo
The 5 languages with the lowest linguistic distance from Tibetan:
A quick 3-question check between Tibetan and Zulu. No signup.