What this means for learners
Cofán and Dioula share 23 sounds — roughly 59% of Dioula's inventory overlaps with Cofán. Shared sounds are ones a speaker already knows from their native language and will generally produce and perceive accurately without explicit training.
The 16 sounds found only in Dioula represent the greatest pronunciation challenge for Cofán 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, Cofán has 14 sounds not used in Dioula. Native Dioula speakers learning Cofán 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.