Jeremy Renner and Hailee Steinfeld both learned American Sign Language to welcome Alaqua Cox to the set.
The TV show was originally tentatively planned as a movie, which was even included in Jeremy Renner's contract. However, Kevin Feige felt that it would be a better fit as a Disney+ show, and Renner agreed to the change.
Maya Lopez/Echo is the second deaf superhuman to appear in the Marvel Cinematic Universe. The first was Makkari in Eternals (2021), played by Lauren Ridloff. Both are played by real-life deaf actresses.
Alaqua Cox is Native American and deaf, just like her character Maya Lopez but, unlike the comic book version, Cox also happens to be an amputee. Rather than go to potentially complex measures to conceal this, the show runners instead fully incorporated this detail into the character as presented onscreen.
Darnell Besaw who played young Maya is the cousin of Adult Maya actress Alaqua Cox. Unlike her cousin, Besaw is neither deaf nor an amputee, so that latter part about the character had to be done with special effects in her scenes.