I have an apple mac laptop and it is driving me crazy...?

for the first 2 months it worked great...then suddenly this little robotic voice started repeating every keystroke that I made...now I cant hear myself think even...the dude is making me mental...even when I want to hear people speak over the net to me in chat...I cant hear them...I only hear the dude. I have searched everywhere trying to figure out how to shut the guy up...I dont even know how he got turned on...can anyone help on this? thanks in advance