This episode has no audio beyond music and the actors say all their lines in ASL. The entire point is to give hearing people a taste of being deaf.
When Emmett said his mom was apart of Gallaudet's school protest in 1988, he wasn't exactly lying. The actress who plays Emmetts mom, Marlee Matlin, was interviewed by ABC News along with Elisabeth Zinser (the hearing president of this deaf college) and Greg Hilbok (one of the main 4 student protesters) about the protest.