What this means for learners
Hopi and Aleut share 23 sounds — roughly 47% of Aleut's inventory overlaps with Hopi. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 13 sounds found only in Aleut represent the greatest pronunciation challenge for Hopi 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, Hopi has 26 sounds not used in Aleut. Native Aleut speakers learning Hopi 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.