What this means for learners
JINGPHO and Ilocano share 15 sounds — roughly 50% of Ilocano's inventory overlaps with JINGPHO. 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 Ilocano represent the greatest pronunciation challenge for JINGPHO 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, JINGPHO has 15 sounds not used in Ilocano. Native Ilocano speakers learning JINGPHO 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.