What I did was ask her (once we were comfortable enough to share these things with each other) was what was/is the hardest thing you have dealt with or deal with currently. After I listened to her and gave her space to share, I shared mine which is my speech and how it affects me. This person in your case likely already knows, but I think the real important part is having a conversation about it and talking about how it affects you mentally. Honesty and transparency is something I value in a relationship and being transparent about it can help ease the pressure of your speech with them. Also as a bonus talking about something so personal and giving them space to share as-well may likely deepen your relationship. And with you bringing it up it shows them that you’re comfortable sharing these things. Good luck!