This is a response you normally get when you don’t speak loudly enough. I’ve gotten this response plenty of times.
But there’s another reason you hear this. It’s when you’ve said something in proper English, but your listener does not understand the words you use. I have a family member who over the years, when I’d say something, would respond with “I have no idea what you just said” or “Speak English!”
I naturally use big words and long sentences. I’ve done that as long as I remember. Part of it’s just how I communicate. Part of it’s because I have complex thoughts and prefer to use fewer but more precise words. I’m an engineer, I like to talk efficiently.
But this bites in me in the butt a lot, even when I’m talking with otherwise English-proficient people. I phrase things just a little too weirdly or formally. I try to pack too many thoughts into one sentence. And now I have to repeat myself, slower, word-for-word, and it takes my listener a few seconds to half understand what I said.
I also tend to go off-script. In a given situation, such as meeting someone for the first time that day, there’s an exchange of pleasantries you’re supposed to do. I guess I can see the reason behind it. But I don’t really care for small talk so I jump into the meat of the exchange a bit too fast, too off-script from how it’s normally done. And I get the proverbial deer-in-the-headlights look.
To some this sounds like I’m whining about how I need to “dumb down my speech” because I talk too smart or something. I don’t mean for it to be condescending like that. But the reality is, I talk like an academic. Most people are not academics. When it comes to writing for the general public to read, the main rules are you should use short sentences and small words as appropriate. You should do the same when talking too, especially in informal situations. Because the more syllables you use, the more thoughts you try to cram into one breath, the more room for misunderstanding.
So maybe I should be more intentional with my speech. And my writing, too. Ease off on the words that are super precise but confusing because nobody uses them. Split my sentences into shorter pieces. Play the small talk game because that’s how people mentally prepare for bigger topics. Basically, try to sound like a human.