Question

while you are on the moon would you able to talk to each other? if not then what is the alternative?

Answer 1

Sound waves need material medium to travel.It can be solid, liquid, gas.

But on moon there is no atmosphere to carry the sound waves.So we can't talk on Moon
We can use radio transmissions to talk to each other.Astronauts use it.

Answer 2

in space there is no air .....and what we called sound actually is vibration of air . sound need a medium to propagate and not like other electromagnatic  radiations like radio waves , cosmic waves , electromagnetic waves etc. 

so we can't talk on moon ..... like astronauts . who .have devices in their helmets which transfer the sound waves from their voices into radio waves and transmit it to the ground (or other astronauts in space). This is exactly the same as how your radio at home works. Radio waves are often thought of as a form of sound because of their use in this way, but radio waves are NOT sound waves - they are a form of electromagnetic radiation analogous to visible light, and therefore can propagate through a vacuum.  :)