Ive heard you should always use I statements because anything else means your trying to control the other persons actions. Ive also heard it said you dont need to give any explanation for your boundary, and saying no is a complete sentence. Ive never done this because in my counseling session the doctor put more emphasis on communicating feelings and stating needs while also acknowledging the other person has a choice in their actions. It wasnt called a boundary but I think its about the same. Goes something like this:
Inform: When you do (her behavior), I feel (your reaction)
Request: Can I ask you to (stop or change this behavior)
If the person doesnt stop the behavior then you repeat by stating how you will handle your boundary being broken:
Inform: If you are not willing to (stop or change this behavior) I will need to (take this protective action).
Example:
When you call me names it hurts me
Can I ask you to speak to me in a calm and respectful tone ?
If your not willing to speak to me calmly/respectfully then I will have to end the conversation.