That is what I do. I have some of the same issues as you. PTSD, anxiety depression, and a history of sexual abuse. So I know exactly how you feel.

I write alot. I journal and my T reads it each week. (T = therapist by the way) I used to write that I "freeze" in conversation. I can't start conversation or make my wishes known. So I write what I feel. I used to do that a lot. I kept a note book with me in T and I woudl write instead of talk. I would write "That scares me" and after the T would ask "What does" , sometimes I could tell her and some times I just had to write what does.

We always start off the session with her reading what I wrote during the week. Then we discuss that. I have had the same T a little over 2 years now.

Good luck. Keep trying.