What this means for learners
Aleut and Kimeru share 19 sounds — roughly 53% of Kimeru's inventory overlaps with Aleut. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 8 sounds found only in Kimeru represent the greatest pronunciation challenge for Aleut 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, Aleut has 17 sounds not used in Kimeru. Native Kimeru speakers learning Aleut 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.