What this means for learners
SIONA and Kabardian share 10 sounds — roughly 16% of Kabardian's inventory overlaps with SIONA. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 53 sounds found only in Kabardian represent the greatest pronunciation challenge for SIONA 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, SIONA has 20 sounds not used in Kabardian. Native Kabardian speakers learning SIONA 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.