Sign Language Query

I'm not sure if this was addressed anywhere else.

But I was curious how accurate the sign language is? I don't know any Sign language so I can't tell.

I'm just curious if its accurate and if the actress learned all those lines in sign language.

Is there a BTS of them talking about that?

Hey 😊,
I’ll start by saying that the only information I found was about the “scandal” (long story short: some Koreans thought the production was mocking people who use sign language with the “middle finger scene,” which led to the production apologizing for it 🙄). Unfortunately, I couldn’t find anything about how Chae So Bin prepared for this role.
What I can assume is that she was likely accompanied by an interpreter throughout the filming process for both Korean and British sign languages.
In high school, my school program included LIS, which stands for Italian Sign Language. From what I remember, there isn’t a universal sign language; each country has its own. So, the only way to determine the accuracy of her signing would be to ask someone who uses Korean Sign Language.
One thing I did notice, which I assume is universally considered positive, is that Chae So Bin is expressive when she signs without overdoing the signs. 😊
EDIT: While writing this, I discovered that someone has subtitled the cast commentary for episodes 1–2, where Chae So Bin talks about her role. Here’s the video: (ENG SUB) When the Phone Rings Episode 1 - 2 Commentary

There are BTS clips & interviews etc on Youtube where you can see her practicing sign language & she is accompanied by someone who teaches her. Also, like someone already posted the episode commentary link, she did study both korean & british sign language to get it right.

Sooo, I'm pretty sure it's accurate.