...to Real time talk into a microphone and on speakers i can hear same message?
That's a PA system or a bullhorn and there's no need for a microcontroller.
...And, the Arduino isn't fast-enough for real-time audio.
...but i would like to have like a "telephone".
Again, land-line phones are mostly analog (you could use the Arduino to make the touch-tones for dialing). Cell phones are very complex although you can get a GSM shield to do all of the "work".