What this means for learners
Sango and Fɔn share 36 sounds — roughly 82% of Fɔn's inventory overlaps with Sango. 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 Fɔn represent the greatest pronunciation challenge for Sango 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, Sango has 8 sounds not used in Fɔn. Native Fɔn speakers learning Sango 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.