Switched at Birth has a unique credit: It is the only show to do an entire episode in American Sign Language. While that episode is a landmark achievement, the Freeform drama has incorporated ASL into every single episode of its show, forcing its cast members to become fluent in it.

Switched at Birth has done a singular thing in including the deaf community so integrally into the show since it revolves around two girls who were switched at birth, one of whom developed meningitis that left her completely deaf. To celebrate Switched at Birth's final season, TVGuide.com asked the cast what sign language has meant to the show and who had the hardest time picking it up.

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Katie Leclerc, who plays the deaf sister Daphne Vasquez, was fluent in sign language before she started the show, but several cast members didn't know any ASL before starting production. It turns out the cast pretty much matches their characters in how they learned and who has managed the best. D.W. Moffett has had the hardest time being able to sign fluently, but Lucas Grabeel picked it up extremely quickly. Having had to go from not speaking to being fluent, the cast did us a solid and told us the essential signs to know if you're just starting out learning ASL. Check it out in the included video.

Switched at Birth returns for its final season on Tuesday, Jan. 31 at 9/8c.