Struggling with Nonverbal Episodes: Need Advice

How do I get out of a nonverbal episode? I've been experiencing them a lot more recently. When I was younger I used to have moments where speaking became difficult due to overstimulation and anxiety, but I was able to basically force myself to talk when needed to appear normal. Now, I find that it is much harder to do that. I've gotten into trouble for it recently and I can't get myself to talk and explain. What makes it worse is that stress related to difficult conversations can sometimes trigger it, in which case the person that I'm having the conversation with assumes that I'm purposely not responding. Of course, feeling like I physically can't talk also causes more stress which then exacerbates the issue.