Only in Lwaa 28
What this means for learners
Lwaa and Mambila share 31 sounds — roughly 53% of Mambila's inventory overlaps with Lwaa. 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 Mambila represent the greatest pronunciation challenge for Lwaa 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, Lwaa has 28 sounds not used in Mambila. Native Mambila speakers learning Lwaa 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.