Only in Yuchi 37
What this means for learners
Yuchi and Chasta Costa share 27 sounds — roughly 42% of Chasta Costa's inventory overlaps with Yuchi. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 17 sounds found only in Chasta Costa represent the greatest pronunciation challenge for Yuchi 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, Yuchi has 37 sounds not used in Chasta Costa. Native Chasta Costa speakers learning Yuchi 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.