If it helps any I can try to describe what it’s like for me when I’m approaching meltdown territory and can’t speak easily:

My skin feels like it’s being electrocuted, with shocking/crawling sensations, especially in my limbs. It feels like I have to pull each thought and word out of molasses to form a coherent sentence, it’s slow and requires a lot of effort. The sound and sensation of my own voice reverberating in my head, even when I speak quietly, is so intense that I only want to use the minimum words possible. My entire body is heavily fatigued, as if I worked out very hard the day before and haven’t rested properly. That’s not even going into ‘normal’ masking stuff that also takes effort, like making sure my tone is right, using an appropriate expression, etc.

When I’m in that state the only thing that’s good for me is a dark room and a weighted blanket. After that (sometimes hours, sometimes a day or more) I’m good to talk about it… if there’s even anything to talk about! Sometimes it’s literally just “I heard too many car horns today” or something like that.