What this means for learners
GERMAN and Dutch share 32 sounds — roughly 55% of Dutch's inventory overlaps with GERMAN. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 26 sounds found only in Dutch represent the greatest pronunciation challenge for GERMAN 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, GERMAN has 9 sounds not used in Dutch. Native Dutch speakers learning GERMAN 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.