What this means for learners
Tamil and Khasi share 28 sounds — roughly 65% of Khasi's inventory overlaps with Tamil. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 12 sounds found only in Khasi represent the greatest pronunciation challenge for Tamil speakers. The adult brain tends to map unfamiliar sounds onto the closest native equivalent — a process that produces the characteristic "accent" of a second-language speaker. Learning to hear and produce these sounds as distinct requires focused ear training, not just repetition.
Conversely, Tamil has 15 sounds not used in Khasi. Native Khasi speakers learning Tamil will face the mirror-image challenge with these sounds.
Phoneme inventories from PHOIBLE. Data reflects one documented inventory per language; some variation exists across dialects and sources.