Sure, I started potty learning with my kids around 12 months, and by 18 months they were in trainers and fully trained (including night) at 22 months.
It's about laying the foundation: reading lots of pottying books, introducing the potty, helping them to get in touch with their muscles, etc.
The idea is that you can teach the concept of potty and all the skills necessary to be potty trained. You don't have to wait till they are 2.5 or 3, you can "teach them" this stuff earlier. And you can! In fact, 90% of the rest of the world has their kids trained by 18 months. Once upon a time (prior to 1950), kids in America were trained by 2. And trust me, it wasn't mommy training. These kids were trained.
Toddlers do in fact take themselves to the potty! Sure, mom suggests going from time to time (like before leaving the house to go to the park), but what mom doesn't do that for young preschoolers?
There is little work involved. I let my kids run around naked, taught them where to put their pee and poop, and by 18-19 months, they were diaper free. Yes, we had accidents for a while, and my just 2 year old son still does occasionally (the I waited too long, pee all over the bathroom floor 2 year old distracted kind!). But it's all about the type of work you want to do. Do you want to change diapers for 3 years, or do you want to invest a little time (10 minutes a day) and have them in undies by 2?
Whatever your approach, I think all households should have a copy of Potty by Leslie Patricelli for their 12 month olds. I started reading this to my son at 10 months,and by 15 months, he was taking himself to the potty trying to pee in it! By 18 months, he refused diapers and wanted to be naked so he could use his potty seat. My son trained himself, because I had lots of potty books and pottys around. It is super easy to motivate little ones to use the toilet --all on their own. You just have to give them the opportunity to learn.