What this means for learners
Turkmen and Ilocano share 18 sounds — roughly 49% of Ilocano's inventory overlaps with Turkmen. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 7 sounds found only in Ilocano represent the greatest pronunciation challenge for Turkmen 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, Turkmen has 19 sounds not used in Ilocano. Native Ilocano speakers learning Turkmen 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.