What this means for learners
Squamish and Yao share 16 sounds — roughly 33% of Yao's inventory overlaps with Squamish. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 33 sounds found only in Yao represent the greatest pronunciation challenge for Squamish 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, Squamish has 21 sounds not used in Yao. Native Yao speakers learning Squamish 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.