Shared sounds 37
What this means for learners
Urdu and Hindi-Urdu share 37 sounds — roughly 39% of Hindi-Urdu's inventory overlaps with Urdu. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 57 sounds found only in Hindi-Urdu represent the greatest pronunciation challenge for Urdu 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, Urdu has 21 sounds not used in Hindi-Urdu. Native Hindi-Urdu speakers learning Urdu 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.