What this means for learners
AIZI and Yao share 22 sounds — roughly 45% of Yao's inventory overlaps with AIZI. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 27 sounds found only in Yao represent the greatest pronunciation challenge for AIZI 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, AIZI has 11 sounds not used in Yao. Native Yao speakers learning AIZI 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.