Blind Speakers Show Language-Specific Patterns in Co-Speech Gesture but Not Silent Gesture

Sighted speakers of different languages vary systematically in how they package and order components of a motion event in speech. These differences influence how semantic elements are organized in gesture, but only when those gestures are produced with speech (co-speech gesture), not without speech (silent gesture). We ask whether the cross-linguistic similarity in silent gesture is driven by the visuospatial structure of the event. We compared 40 congenitally blind adult native speakers of English or Turkish (20/language) to 80 sighted adult speakers (40/language; half with, half without blindfolds) as they described three-dimensional motion scenes. We found an effect of language on co-speech gesture, not on silent gesture-blind speakers of both languages organized their silent gestures as sighted speakers do. Humans may have a natural semantic organization that they impose on events when conveying them in gesture without language-an organization that relies on neither visuospatial cues nor language structure.