Only in IRISH 51
What this means for learners
IRISH and Bulgarian share 18 sounds — roughly 26% of Bulgarian's inventory overlaps with IRISH. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 31 sounds found only in Bulgarian represent the greatest pronunciation challenge for IRISH 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, IRISH has 51 sounds not used in Bulgarian. Native Bulgarian speakers learning IRISH 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.