If your phone has been tapped, it would be nearly impossible to detect with any certainty. The CIA have come up with technologies to mask the sound of what a phone is transmitting – this means that they can listen and record you through your own device without alerting you.
Another way the CIA could tap your call would be by installing at remote bug or microphone real close to where you use your phone. This may not be a high-tech process anymore because it can laser cut just about anything these days, so anything’s possible really…! What we do know is that surveillance experts always believe there are ways of hacking into any system – so if your call is being monitored then I’m sorry but chances are, it will be very difficult to find out.