Sundanese vs Indonesian

Sundanese and Indonesian share 23 sounds — roughly 74% of Indonesian's inventory overlaps with Sundanese. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.

The 8 sounds found only in Indonesian represent the greatest pronunciation challenge for Sundanese 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, Sundanese has 3 sounds not used in Indonesian. Native Indonesian speakers learning Sundanese 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.