This study investigated whether auditory experience is necessary for the typical development of volitional nonverbal vocalizations. Acoustic analysis of vocalizations from profoundly deaf and hearing adults revealed that deaf adults produced unconventional and homogenous vocalizations of aggression and pain, characterized by high pitch, lack of articulation, and fewer harsh nonlinear phenomena. Conversely, their fear vocalizations were relatively typical. Perception experiments confirmed listeners' difficulty in identifying the intended emotions of deaf vocalizers' vocalizations, perceiving them as less authentic, and reliably detecting deafness. Congenitally deaf adults with zero auditory experience showed the most atypical vocalizations, suggesting an additive effect of auditory deprivation. The findings indicate a role of vocal learning in acquiring the full repertoire of volitional non-linguistic vocalizations.

Katarzyna Pisanski, David Reby, Anna Oleszkiewicz