Why do kids repeat what you say?

So this isn't something proud to blog about but it has finally happened. Grandma's stop reading now. Chandler said a vulgar word...after I said it. Oh! S#*@! I know, I know but what would you say if you were taking homemade chicken noodle soup to a family for dinner and you dump it out on the floor of your new car! Ya that's what I thought. Okay it really is no excuse so I told Chandler next time I say a bad word then he can spank mom's mouth!