What this means for learners
Cheremis and Atayal share 18 sounds — roughly 53% of Atayal's inventory overlaps with Cheremis. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 9 sounds found only in Atayal represent the greatest pronunciation challenge for Cheremis 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, Cheremis has 16 sounds not used in Atayal. Native Atayal speakers learning Cheremis 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.