Question

How can astronaut talk in space without any special device.

Answer 1

Without any special devices they can't talk each other.
because sound need a medium to travel.in space there is no medium is present.


Usually there will be an electronic device inside their helmet which helps them to communicate.

(AThey must need some sort of electronic device which converts sound to electical signal at speaker side and electrical signal to sound at reciever end for sound propagation.)