What this means for learners
Yay and Madurese share 25 sounds — roughly 66% of Madurese's inventory overlaps with Yay. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 10 sounds found only in Madurese represent the greatest pronunciation challenge for Yay 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, Yay has 13 sounds not used in Madurese. Native Madurese speakers learning Yay 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.