Only in Ukrainian 31
What this means for learners
Ukrainian and Yao share 10 sounds — roughly 20% of Yao's inventory overlaps with Ukrainian. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 39 sounds found only in Yao represent the greatest pronunciation challenge for Ukrainian 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, Ukrainian has 31 sounds not used in Yao. Native Yao speakers learning Ukrainian 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.