Given the origin, wouldn't the powerful voice be speaking an indigenous language like Tupi-Guarani , Warao , Kariña or Arawak or perhaps the more widely / commonly spoken Spanish or Portuguese ?
Well I suppose after so long in the country he would be fluent in German too and as a cosmic phenomenon / spectre it would make sense that the spectre and his premonition was linguistically understood.
The afterlife has a universal translator, I thought this was common knowledge? SMH