What this means for learners
JEBERO and Indonesian share 15 sounds — roughly 48% of Indonesian's inventory overlaps with JEBERO. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 16 sounds found only in Indonesian represent the greatest pronunciation challenge for JEBERO 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, JEBERO has 8 sounds not used in Indonesian. Native Indonesian speakers learning JEBERO 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.