[yorkietalkjilly]

You really don't have to train them to tell you. Usually if you take them out regularly, they will start to go to the door and whine, or stand at it and look at it and then you, paw at the door, sniff at the crack of the door that opens - things like that. Other dogs will stand still and stare at you and if you ask them if they need to go outside, they will jump about, go around in circles or otherwise indicate "YES!". Each dog will "tell" you in his own way. When he is doing any of those things he does to indicate it is potty time, you can then say "Bark" or "Circles!" or show him whatever you want him to do and when he does, treat him and take him right out. Then in time he will come and do that activity to get to go outside.

But even without a bell or anything, a dog will let you know when he wants to go outside in time. Right now, you just watch for his body language to show you he needs to go such as circling, excited sniffing of the floor, running about sniffing, starting to move his tail up and down, staring/pawing/sniffing/barking at you or the door to the yard, or the obvious one - starting to squat or hump up. But as he learns more, he will start to focus on you or the door when he needs to go out and he'll let you know more in advance than he does now.