The only thing that works for me is to avoid sensory overload.
I don't have much control over the amount of sensory overload going on around me.
I usually have 1-3 shutdowns in a week, sometimes far more, very rarely do I have a week where it doesn't happen at all. If I try to hold one off then I start losing other things like speech, the ability to read, the ability to write, the ability to translate words into images or images back into words, the ability to move, the ability to process sound, the ability to process vision...
Most often though, I just end up letting it happen and laying down for a few hours. During that time I can't really move or speak or do anything, and once it passes I usually go to sleep. If I don't, sometimes effects like those that happen when I try to resist a shutdown kicks in, which accounts for many of the occasions I've lost speech.