Going from Tigrinya to Quechua (Runa Simi) has a composite linguistic distance of 86% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Ge'ez → Latin
Afro-Asiatic ↔ Quechuan
The 5 languages with the lowest linguistic distance from Tigrinya:
A quick 3-question check between Tigrinya and Quechua. No signup.