My ADHD manifests this way as well and I explain it as, "I'm sorry, I didn't understand English just then." I only speak one language but it's true, I couldn't parse their language.

I also picked up a "quirky" habit where I'll say the nonsense phrase back at the person, who gets a laugh, then repeats themselves. Since it seems like I'm being cute and quirky instead of having an auditory processing disorder, people don't get annoyed as often.