How do you center an entire television series around someone who can’t talk? That may seem like an impossible feat with no answer, but Marvel actually faced this daunting task when it came to the comic book property’s latest show Inhumans. Black Bolt (Anson Mount) is the King of the Inhumans–the alien/human genetically-engineered race who live in the city of Attilan on the moon–but his power is extremely destructive. As in atomic bomb-level destructive. If he talks, his voice could level an entire city. So he learned to control his powers at a young age, opting to never speak aloud again.

While that’s easy to depict in comic books, the ABC series had to figure out a way to allow Black Bolt to communicate with his wife Medusa (Serinda Swan) and the rest of the Inhuman royal family. Marvel worked with Mount and Swan to actually come up with a whole new sign language to use on the show.

“I can’t… use ASL because he’s not from [Earth],” Mount told Nerdist on the set of Inhumans in Hawaii. “I have a sign consultant; I’m developing a lexicon as I go [and] I’m borrowing some of the underlying rules of ASL and what makes it work efficiently.” While he enjoyed this particular acting challenge, it was by no means easy. It required hours and hours of work before shooting even began. “It creates homework and it creates choreography and it creates getting things into the muscle memory,” Mount said. “I have to get it so into my muscle memory because I can’t be thinking about it and acting at the same time. It’s not easy.”

It wasn’t just Mount who had to learn a whole new language for Inhumans, as Black Bolt’s wife Medusa, Queen of the Inhumans, acts as his translator. Swan smiled as she thought back on all the prep work she and Mount did to perfect their sign language. “We just worked really hard before it started. We worked really hard, and got in there like, ‘All right, let’s do this,'” she told reporters on set. “We found little idiosyncrasies, found the beats, found the moments. Once I got it, I was like, ‘Cool!'”

At first, Swan was taken aback when she learned that her scene partner wouldn’t speak at all and that she would essentially be speaking for him. “I was like, ‘Oh, so it’s like two roles,'” Swan said. “[I’m] his translator. But you can’t lose your character when you do it. So it’s this really interesting duality between keeping Medusa’s presence and not fading away, and also honoring the king and what he represents to the people of Attilan. So we definitely worked hard.”

What excited Mount the most about playing Black Bolt was not the fact that he had such an incredible power, but rather the fact that his power was so terrible. “It’s great because I don’t look at it as a power,” he said. “That’s one of the great things and one of the ways in which Black Bolt is really well drawn. It’s smart. He is the leader who must be aware of the power and potential danger of his public voice. I think he’s immediately charming in that way.”

Mount adds, “Readers appreciate Black Bolt because they see him struggling with a deep sense of responsibility. A king’s identity–a responsible king–their identity is the state. And he certainly is that.”

One of the ways in which Black Bolt learned how to control his voice at such a young age was by the use of a Quiet Room, where his power could be contained, and which Inhumans brings to life gorgeously. The Quiet Room set was built in its entirety to allow the IMAX cameras to really show some true movie magic. Seeing it in person was awe-inspiring, and seeing it on IMAX screens will surely give comic book fans a thrill.

“When he came out [of terrigenesis, the process in which Inhumans transform and get powers], his power was so frighteningly intense,” Mount said. “He sneezes, he blows away half the world. So before he had learned to control it, he was shut away in this Quiet Room that literally funnels the energy of his voice… out into the stratosphere. He finally got control over it and himself and was able to leave, but it’s still there and it’s still where he goes to meditate.”

In the Quiet Room is also where Black Bolt and Medusa created their sign language, as well as fell in love. “Medusa, being the badass that she is, and the reason why I love playing her, enters into the chamber where he is kept and they start building a language together,” Swan said. “Over time, through love and this amazing connection, they build this sort of symbiosis between the two where he does sign, but she already knows most of what he’s saying. She knows the tone and they’ve practiced… which is something Anson and I did when we first got here.”

Are you excited to see Black Bolt’s new form of sign language come to life on Inhumans? Tweet me at @SydneyBucksbaum and let’s discuss!

Inhumans will premiere the first two episodes exclusively in IMAX theaters on Sept. 1 for two weeks (tickets available here) before its debut of the full series on Sept. 29 on ABC.

Images: Marvel, ABC

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