What this means for learners
Rundi and SEDANG share 13 sounds — roughly 24% of SEDANG's inventory overlaps with Rundi. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 42 sounds found only in SEDANG represent the greatest pronunciation challenge for Rundi 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, Rundi has 16 sounds not used in SEDANG. Native SEDANG speakers learning Rundi 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.