What this means for learners
TETUN and Cebuano share 10 sounds — roughly 48% of Cebuano's inventory overlaps with TETUN. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 11 sounds found only in Cebuano represent the greatest pronunciation challenge for TETUN 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, TETUN has 9 sounds not used in Cebuano. Native Cebuano speakers learning TETUN 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.