[Radek]

This unsatisfactory method of winning combats is called "fake talk" method. The method is based on the fact that combats in BG run in turns. Each turn is 6 second long. If you pretend that you are about to talk and if you attack instead, the victim of the fake talk will wait for your conversation and overlook the attack during the current turn. It would detect the attack next turn - if you allowed it. You can prevent the detection by means of pausing before the turn ends and pretending the talk again.
We can see why this "method" is stinking: we are taking advantage from a misunderstanding in the game. The scripts of the monsters aren't prepared for your "sudden change of decision". This could be fixed by introducing an I_have_been_attacked flag in the scripts. When the flag is set then no more talks. Prepare to die.