I’m sure you don’t mean the learn mode which has double subs, Korean or Chinese on one line and English on another? Because in this case “learn” refers to “learn the language”, not “learn how to write subtitles”
Unless you know one of the source languages and you want to see how English subbers have translated from it. But if you know the source language, you can know by listening, why do you need to see the captions in that language?
In my subbing course, I use Google sheets a lot.
I copy the subtitles of an episode on a Google sheet and the learners write their translation next to the original. Then I mark the problem subs (highlighting the cells with a different colour) and then we discuss what’s wrong with them and how to make them better. I try to gently guide them to make their own corrections. If they can’t come up with something I give suggestions explaining why, and I always try to convey that there’s not only one right answer, there may be a few different ways to say the same thing.
All the students can view the same Google sheet at the same time, and we use Skype to talk among us, so everyone gets to give feedback and ask questions.
After this, I use Google forms to create tests. Sentences to be translated. Those are chosen from dramas but sometimes adapted to contain more “trap” words (like false friends) or idiomatic expressions which I know are routinely translated wrong in my language.
Only after this will I “unleash them” on an actual drama.
This method helps those newbies who have zero subs and no Vikipass so they can’t access most dramas get the necessary experience and be guided on their first steps, because they will know of the most usual challenges they will face before actually being thrown into the water and being told “Now either swim or drown”.
Sometimes one can quietly practice on Subtitle Editor by writing on an untranslated rare language like Klingon and then of course delete everything before anyone sees it. If you’re not the CM, you have to ask for permission before doing this, of course.
What’s really strange is that people are asking to subtitle difficult dramas when they don’t understand English that well and very often don’t have the basics of their own language.
I had someone do a little test recently, and she translated the sentences very vaguely. The meaning was “almost” it, and some parts were skipped. It was obvious that she didn’t fully understand the English she was reading (and possibly didn’t bother to look it up?). If you don’t understand, how can you expect to translate?
I understand that some people are not aware of lacking in grammar and punctuation in their own language. This can happen.
But you surely are aware of the fact that you don’t understand everything you’re reading. So with what nerve are you asking to be a subtitler on a show about secret intelligence services, with LOTS of technical terms that I’ve spent half the night researching not only in English but in my language?