Shared sounds 37
What this means for learners
Mambila and Mambila share 37 sounds — roughly 86% of Mambila's inventory overlaps with Mambila. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 6 sounds found only in Mambila represent the greatest pronunciation challenge for Mambila 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, Mambila has 3 sounds not used in Mambila. Native Mambila speakers learning Mambila 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.