To some parents training their kids to use the regular toilet is probably easy. In my family, I tried to introduce the toilet to my four year old since he was two years old and screaming is what I always get. As I was taking the psychology class the instructor mentioned about not forcing the kids to toilet training because they will come to that phase that they will just want to use the toilet on their own. Well, I would say that it is true. After two years past my four year old boy just use the toilet freely, no forcing involved and no accident on his pants. If he feels that he needs to use the toilet he normally yells "pooooooopy" or sometimes I saw him sitting on the toilet on his own. He still have some adjustment to work on during the night,bur he is getting the idea now. I haven't really work with him during the night since he still on lasix, and he pee a lot after giving that meds. Not fully toilet trained yet, but he is getting there :).
Now, since the word poopy gets my attention most of the time, my sixteen month old daughter uses this word to get my attention too. Not only that she will insist to sit on the toilet :) I guess that is a good thing so that I can toilet train her earlier than her brother.