Clearly, Identity Theif was not a movie that anyone had to pay attention to, it probably wasn't even one that needed to be watched at all for the sheer lack of anything actually entertaining going on in it. "I happen to know that asking where the toilet is probably isn't that important, so I'm very curious about this other sign you remember."
Even Clint wasn't necessarily fluent in ASL, he'd never been particularly good with languages, but he'd always been very good with his hands, he'd managed to pick up enough that he could carry out a moderate conversation about random things and day to day life with the therapists at the VA before he'd been discharged.
"I mean, that's pretty much why I got good at lip reading because it's kinda shit to just expect people to understand ASL." And because Clint actually tended to avoid bringing up his hearing issues.