Q: how can you turn off airplay on iphone 4?

"Turn off"?

I thnk you mean you would like the audio/video outputs to be sent to the iPhone instead of an external device.

Open Control Center by swiping up from the home button.  Click the "AirPlay" icon there.  Set the output as you wish.

When i go to control center & click "Airplay" icon, i don't get any such option ! i just get another drop down menu with two options 1) a speaker symbol with a tick mark against it ( i cant change anything there)

                         2) "Cancel" option !!

During the time when airplay gets activated the phone speakers dont work for any function, neither for calls nor for music etc.

hsiphone4 wrote:

 

During the time when airplay gets activated the phone speakers dont work for any function, neither for calls nor for music etc.

Correct.  Audio output goes to the AirPlay device.

hsiphone4 wrote:

 

When i go to control center & click "Airplay" icon, ... i just get another drop down menu with two options 1) a speaker symbol with a tick mark against it ( i cant change anything there)

                         2) "Cancel" option !!

Then there is no other AirPlay device on your WiFi.  Check the fourth slide here ("choose your device"):

http://support.apple.com/kb/HT4437