Now, re-learning how to speak, or rather how to speak effectively to a two year old takes lots of mindful practice. It cannot be done overnight that's for sure.
"You don't want the toast?" is completely lost on a toddler. Stating the negative (even as a question) will plant the suggestion that she truly does not want the toast, and I'm stuck having just told her that she doesn't want what I'm trying to get her to eat or do. Instead, "Do you want the toast?" usually followed by some tasty description of how good it looks, or simply leaving the toast (or other item) out for her, eventually she'll make her way to it. Then of course there's the complimenting of what a good job she did eating, getting dressed, sitting still, using library voice, etc. Catch more flies with honey than with vinegar---positive reinforcement works wonders.
"Don't stand up!" vs. "Stay seated!" is another communication error, I gratefully remedied early on. Little children must first understand the positive of the statement before they can connect the negative. So, telling an 18 month old "Do NOT stand up" all the child registers is "stand up". "Stay seated" is much more positive and certainly easier for a toddler to understand.
I've realized that positive communication is handy with adults as well. Speaking in the positive, being aware of my semantics, simple changes in my words, "bad" & "good", replaced with "unhealthy" & "healthy." Learning how to say what I want or what the goal is rather than focusing on what I don't want. I have found it much easier on the psyche, less energy-sapping to focus on positives, instead of constant maintenance blocking the negatives.
Telling a toddler what is not allowed is most effective to create a caterwauling child, especially if her goal is the opposite of what I had in mind. However, if I pair it with what she CAN do, then she is distracted with what I've just provided as a new challenge or option, and problem solved. I can fold the laundry, clean the surfaces, remediate messes, in peace. If I really want to distract Little Girl I'll tell her what she CAN do, without mentioning at all what I'm avoiding, a modicum of control without overt display of control.
A small rant aside---
Consider this modicum of control with a governing body. Much of the time we are so concerned with making absolutely sure that we can do something, writ by law, that we forget in defining what we can do we are also defining we cannot do. In turn this creates more and more laws, a bigger government happily telling me how & what to do with my health, money, & time---'cause apparently I'm not smart enough to figure it out myself.