Manna has been a reality for more than a decade. Practically the entire warehousing industry uses a fully automated voice system that's almost exactly as Brain describes. An increasing number of retailers are using headset communication with both human and automated elements - your headset receives voice messages from co-workers, managers and automated systems.
Voice picking is already being rapidly supplanted by human-less (robotics) processes. If the cost of implementation for these systems ever dips low enough then a terrible number of warehouse jobs are going to disappear nearly overnight.
https://www.lucasware.com/voice-picking-introduction/
https://www.x-hoppers.com/