Yes you can break the speed of sound, a plane has to go 667 knots. the first person who broke the sound barrier Chuck Yeager flying an X-1 on October,14,1947.
At speeds of 950 to 1,000 km/h (590 to 620 mph) the air flow around the aircraft reaches the speed of sound, and it is reported that the control surfaces no longer affect the direction of flight.