What to say when teaching your child how to set boundaries

"Even if it is your school teacher or your auntie, if they overstepped your boundaries. Make sure to let them know."
"Be precise and clear of what you want and don't want to be spoken at/to be touched in/to be treated as/.."
"Be consistent of your set of limits. If your school mates treated you with disrespect numerous times, make sure every single time you let them know that they've crossed their lines."
Teaching your kids the first small steps in creating their own boundaries will be the best thing you could ever do to them.