It only works if you are inseparable from the child, and-- as pinkballerina said-- spend all day staring at their face waiting for the scrunchy face or whatever their ‘cue’ is. If the child is under 12 months, you are training the parents only, not the baby. If there is anything you value doing more with your time than pretending to toilet train an infant (for bragging rights? Saving a few bucks on daytime diapers? Not sure what the reward is, really)-- like eating, showering, jogging, reading, spending time with other children, not to mention working or otherwise stimulating your self-- it won’t work.
The truth is children can achieve true continence long before the age of 2. In many developed, first-world cultures it is unacceptable for a child to reach the preschool years and not be toilet-trained. We tend to let the child show evidence of cognitive awareness of their own body, to show interest in the potty, to have the speech/language faculties to ask for it, etc before we begin training in the US, which is perfectly fine. Many cultures (not just hut-dwellers who whip out naked babies on the forest paths) start around 12 months, and children achieve control by 18 months. The nerves which supply the colon and urethra itself have completely myelinated by age 11 months-- meaning that children physiologically can achieve voluntary control of their sphincters starting at that age. Again, though EC depends not on teaching continence but on training parents to recognize signals, and does not lead to toilet-training in the important sense until children are well into toddlerhood.
Personally I plan to start with my son (age 15 months) very soon. We are moving house this month and once we are established in the new one, we’ll begin. He is cognitively advanced enough to grasp what the potty is for once he’s placed on it; he can follow both parents into the bathroom and grasp what’s going on there; after a few weekends of serious effort and reptition I think he will grasp it. I hope, but don’t entirely expect, him to be trained by the time his sibling arrives in [name]December[/name], when he’ll be 21 months old. In the Middle [name]East[/name], where his father is from, children are toilet-trained very early; his father was completely trained at 18 months and his aunts at 14 and 16 months, respectively.
Again, I know I’m rambling a bit but I think what separates EC from this philosophy on toddler toilet training is a) EC requires really, really hard-core Attachment Parenting, which is incompatible with most people’s lifestyles and desires; b) EC start with children so young that they anatomically cannot achieve continence or control, and as such is training the parents rather than the babies’ c) EC is much more accident-prone in that diapers are avoided during daytime which obviously has consequences for your home, car, friends’ homes, etc; d) toddler toilet-training involves cognitive recognition on the part of the child that s/he is eliminating waste, and that one does so in this special receptacle, and that one can ask to be brought to it when one needs-- i.e., it’s true toilet-training.
The average age for completion of toilet-training in the US is 3 years, 3 months. [name]IMO[/name] it’s perfectly fine to wait that long if you choose, as long as your children’s preschools don’t require them to be trained before entry.