What this means for learners
KEFA and MANCHU share 15 sounds — roughly 56% of MANCHU's inventory overlaps with KEFA. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 10 sounds found only in MANCHU represent the greatest pronunciation challenge for KEFA 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, KEFA has 12 sounds not used in MANCHU. Native MANCHU speakers learning KEFA 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.