If we don't use our words, we won't be indistinguishable. (What's wrong with saying, "use your words"? Many, many things, including the part where it's ignoring communication that you actually did understand because you didn't like how it was phrased. Thanks, Neurodivergent K.)
But it's not just about words, is it? Once we're using words, you want them to be the "nice," polite words that don't challenge your ideas of how the world works. You want them to be your words, not our words. You want them to be in the right tone, which is, again, polite, and definitely not angry or demanding. (Why is it only called demanding when we're demanding to be treated as human, not when you're demanding we do things like make eye contact or stop flapping?)
And then you want us to understand all sorts of things from your communication that weren't actually conveyed in words. So how about this: USE YOUR WORDS. Not your tone, not your social codes about connotations and extra layers, not your body language. If we don't get to use ours (the different ways of flapping mean things, didn't you know) because you won't understand, or you'll pretend not to, because you want us to use our words, then guess what? You can use your words.
Your tone of voice is not inherently easier to read than mine. Your body language, with shifts in how you stand, is not inherently easier to read than my flapping. Your facial expressions are not inherently easier to read than mine. Your layers and layers of meaning behind your words conveyed in all those things are not inherently easier to understand than my flapping and grunting, and in fact they are a heck of a lot more complicated than my statements that mean exactly the words I said.
And yet. You get to tell us to use our words, and this is somehow completely sensible. It doesn't matter that we've got a disability that literally makes it harder for us to use our words. We have to use them anyways, and it's not even our words we're really supposed to be using. We, on the other hand, don't get to give you the same demand: most of you all don't have any disabilities that make language use harder, and those of you who are demanding we use are words are usually doing so in a language you're fluent in too. That doesn't matter. Some huge percentage of your communication is happening through not the words, so have you considered using your words?