What this means for learners
FASU and Dafla share 9 sounds — roughly 33% of Dafla's inventory overlaps with FASU. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 18 sounds found only in Dafla represent the greatest pronunciation challenge for FASU 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, FASU has 12 sounds not used in Dafla. Native Dafla speakers learning FASU 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.