when my oldest dd was 6 months old, she would make a funny noise when she needed to go potty... we would put her (holding her) on the toilet and she'd do her job... had her day potty trained by 18 months.
When DGD was 12month old she would be dry in the mornings so we'd sit her on the potty chair and she'd pee and then we'd put her diaper on. She was completely day trained and mostly night trained before she was 2 till the daycare she was attending fired her teacher... she reverted back and it took us till she was almost 4 to get her completely trained... Yes, they know more than we give them credit for and things affect them more than we realize.