Only in Balinese 1
What this means for learners
Indonesian and Balinese share 23 sounds — roughly 74% of Balinese's inventory overlaps with Indonesian. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 1 sound found only in Balinese represent the greatest pronunciation challenge for Indonesian 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, Indonesian has 8 sounds not used in Balinese. Native Balinese speakers learning Indonesian 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.