What this means for learners
Squamish and Haida share 26 sounds — roughly 52% of Haida'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 24 sounds found only in Haida 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 11 sounds not used in Haida. Native Haida 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.