How to Say I Don't Understand

I don't understand is not even really a proper word, it's just the sound. So if you don't understand something, you might be like, and you can't do this without making a strong facial expression again. Sounds like you're meditating or something. Like, I don't want to think there's something wrong with me. And obviously if you're wanting to improve your speaking, you're not wanting to give people the impression that you don't speak English well. Later we'll tell you also what to say instead of saying, I didn't understand.