My friends toddler called me a bastard and i told her that she should be more responsible and what would you do if that would happen?

The toddler doesn't understand the meaning of the word even if he /she sounds like they do, and shouldn't be punished or disciplined for copying adults. It's up to the parent to stop with the language or stop others from swearing in front of the child. I think you did the right thing in telling your friend she should be more responsible.

I'd smile at her and ask her if she had any idea what the word means. If she didn't I'd tell her it's a word she shouldn't be using on another person.

I might explore whatever it was I might have said or done to make her unhappy with me, since clearly she does understand that it is not a name we call someone we are happy with, but that is a secondary issue. She should not be calling anyone a bastard.

I would also discuss this with her parent. I don't think punishing her would be the best course of action, although your friend might want to pursue some sort of corrective action. It could include punishment, but that would be for a parent to decide, not the friend of a parent.

I would just ignore it the first time, but if it was repeated, I would just say that that isn't a very nice word, then distract the child with a game or story or similar. Don't make a big deal of it. Children usually pick up these words and try them for a reaction. If there is none, they are usually soon forgotten. If it's constant, then speak to your friend and say that the child seems to have picked up an unsuitable word.

tell her that i didn't think it was appropriate,

although unless i had young children who might pick the language up as well i would probably not do any more than mention it to her.

If i had children, i would be p!ssed, and i would tell her i expected her to discipline the child or at least sit it down and explain what it did wrong. Because only the mother or father will have a real effect at that age.

what? punish the child and ask his or her parents to discipline the child. you have a right since he said something mean to you.

Stop going over their house. The child doesn't know what the words mean. Sounds like bad parenting to me.