What this means for learners
Adzera and Cham share 14 sounds — roughly 40% of Cham's inventory overlaps with Adzera. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 21 sounds found only in Cham represent the greatest pronunciation challenge for Adzera 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, Adzera has 11 sounds not used in Cham. Native Cham speakers learning Adzera 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.