According to translations section in following link , forum is looking for quality translation project.
https://swift.org/documentation/
So I let them know this https://forums.swift.org/t/ive-translated-the-swift-programming-language-documents-into-korean/27758 but I didn't get any responses from it.
Did I write in wrong place? 
I think some of the relevant people may be on holiday. I’ll ping some people who should know better for you:
That would be helpful!. Thank you @Karl 
I'm not actually sure of the best person to tag for this! @nnnnnnnn, do you know? (Is it you?)
@Tommy, my apologies for the slow response! We're working internally on a response, and will have an update for you soon.
@nnnnnnnn Cool! Thank you for the response. 
Hello. Any update on adding a link to the Documentation section? I’m working on a Spanish translation but if I see that links don’t get added to the Documentation section don’t get added, it makes the effort kinda pointless since it wouldn’t get any visibility.
Also, @Tommy, I’m also using GitBook but I’m doing everything manually. Did you find a way to make the process easier/faster? Like extracting the epub, translating the files and bundling it up again?
Also, a tip for updating it to the newer version, you could unzip both epubs and use a diff tool to see what changed between versions.
@georgealegre Unfortunately, I just do it manually after update. I know it’s somewhat painful. Maybe I will be able to make some script for it.