What this means for learners
Aché and Hakka Chinese share 9 sounds — roughly 19% of Hakka Chinese's inventory overlaps with Aché. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 38 sounds found only in Hakka Chinese represent the greatest pronunciation challenge for Aché 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, Aché has 25 sounds not used in Hakka Chinese. Native Hakka Chinese speakers learning Aché 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.