Hello:
What do I have to say to my 3 and 4 year-old kids when they say bad words about their mother and myself.
They call us bad names whenever we refuse to give them what they ask for.
I know its because they are kids and they do not realize what they are saying , but still, how can I educate them to stop.

There is an old Talmudic saying that little children repeat what they hear at home.
I don’t mean to say whether they learned these words at home or somewhere else they feel comfortable ie school, but they most probably didn’t hear them from a passerby on the street and start copying them.

I would first look for the cause, that is where they learned the words and take measures to stop it in its tracks.

As far as their using them now, you have two choices: ignore and it will probably stop very soon, or offer rewards if they speak nicely. Or possibly a mixture of both. At 3 & 4 punishing them might or might not work, especially since they don’t appreciate fully what they are doing wrong.

Kids know how to push their parents buttons, and when they get a rise out of you by saying these meaningless words (at least to them) they get your attention. Ignore these words as if they didn’t even say anything, pretend they didn’t even talk, they will soon lose interest in them, since they are counterproductive, not only don’t they get your attention they get ignored, which is the worst punishment for a small child.

Good luck!