hehe, I had 2 pay 25000 gold on morrowind once.
This is really simple to sort out, just have areas where pk\'ing is enabled or disabled. Lets say if u get attacked inside an area where it\'s disabled then you dont suffer damage. But once you leave that area people are allowed to attack you and you do get hurt. People who dont want to fight dont have to leave pk\'ing disabled areas.

For start the NPc\'s should recognise different questions. In english u can use different questions to ask the same thing. Or make it that the NPC\'s just recongnise certian words. If somebody said the words \'want sword\' to you, you would probably assume they were asking for a sword.