Hey mom, I'm a little confused - your toddler does address you as something, right? Does she address you with your name? Maybe it's because your hubby or any other family member calls you by your name? And if you don't call your hubby by his name, it is possible that it's the reason why your toddler does it only with you and not with him. Each time your toddler addresses you as something else, say the word you want to be called as. Do it nicely and soon your toddler will respond :)
Kids see moms as their own extension and hence do not believe in paying special attention!!! Don't worry..one fine day he will start saying mom and then you will have to ask him to stop saying that!!