What this means for learners
ITELMEN and Aleut share 14 sounds — roughly 39% of Aleut's inventory overlaps with ITELMEN. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 22 sounds found only in Aleut represent the greatest pronunciation challenge for ITELMEN 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, ITELMEN has 18 sounds not used in Aleut. Native Aleut speakers learning ITELMEN 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.