Going from Amharic to Khmer (ភាសាខ្មែរ) has a composite linguistic distance of 88% (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 → Khmer
Afro-Asiatic ↔ Austroasiatic
The 5 languages with the lowest linguistic distance from Amharic:
A quick 3-question check between Amharic and Khmer. No signup.