It all depends on the child. Yes, some will learn earlier than others. Sometimes it's simply that the parent hauls the child to the bathroom every hour and holds him on the toilet until he goes, sometimes it's that the parent knows exactly when the child will go and takes them then. If you don't want to do that or can't, then you need to wait until your child is ready to learn and can let you know when he needs to go. I suggest getting a good pottty training book and reading the "getting ready" chapters.
I started actually training my daughter at 27 months. Before that, she refused to sit on the potty and I was not going to physically restrain her and force her to sit there. She is 29 months now and pretty much trained. She goes to the potty on her own and just needs me to help pull her pants back up.
at 7:42 PM on Dec. 30, 2008