This Way to Talk With Toddlers & Reinforce Language Skills is More Than "OK" - OK? Here's What Not to Do! by Cheryl Leahy
When talking to toddlers or preschoolers, many of us use the word "OK" fairly often, as in: "We're going to take a bath now, OK?" The problem with this is that we are giving them the opportunity to say no, it isn't OK! It also gives them the impression that they are in charge.
A better way to communicate is by asking them if they understand. If you think they don't, have them repeat the action back to you. I also give my son a five-minute, two-minute and one-minute warning so there are no surprises. I have learned this the hard way, but it works for me!