What this means for learners
Island Carib and Lahu share 15 sounds — roughly 33% of Lahu's inventory overlaps with Island Carib. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 31 sounds found only in Lahu represent the greatest pronunciation challenge for Island Carib 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, Island Carib has 14 sounds not used in Lahu. Native Lahu speakers learning Island Carib 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.