Thank you for pointing this out. I have been thinking about this a lot lately, this is my take on the matter for now.
I agree entirely that there is a tendency to use much harsher and much more insulting words than what the Korean actually means. Insults are difficult to translate across any languages, as equivalent insults are very rare. It is very important to take the context into account when translating those words, and not use the same one English swear word for every instances where one Korean word appears. We need to remember that there is also an important part of the insult that is conveyed through the way the person talking transgresses the socially acceptable manner they should address that person. Here is what I mean: in Korean, the social level is stressed in the speech, it is directly “visible” with the way people address each other, and it is extremely important for everyone that people address each other using appropriate social level markers in their speech. To someone from a culture where there is no such thing, talking a bit casually about a superior or senior might not seem like such a big deal. But in some other cultures, just calling a superior (or anyone with seniority over you) by their names (even not in front of them) is already a sign that you don’t have much respect for that person as your superior. And this is only one example, there are a lot of even more nuanced ways of showing respect in your speech than what we might be seeing in some cultures.
Now that I think of it, the respect perspiring in the speech most probably exists in every culture but is harder to decipher when the grammar isn’t affected by the respect you show for the person. In Korean, it’s right there for everyone to see and hear even if you haven’t been bathing in that culture your whole life, and you do not need to decipher the small signs to understand there is a disrespect. You do not necessarily need to use vulgar words or gestures to show your disrespect, the way you speak about them is a dead giveaway. Which means that you can use that to decide how to translate the “insulting” term you hear in the dialogue: the more the person being insulted is supposed to be treated with respect, the more insulting the swear word will seem to them. If all formalities are dropped, the insult is intended to be very strong and show a total loss of respect at that moment. But at the same time, we cannot use a stronger word than intended just because the speaker uses informal speech: telling your boss they are an idiotic fool is a big deal no matter the culture (maybe?), and most of the interpretation comes across through the acting anyway. So I don’t think using overly offensive terms is the right thing to do, because no matter the culture we all understand though the scene and the acting the respect someone is supposed to be due.
All this to say, that we need to read the mood when translating the three or four “swear” words we hear in Korean dramas all the time. jassik is an endearment when a mother talks about her child. It’s a big mark of disrespect when a young employee addresses their superior (how can a twenty-something call a forty-years-old boss “offspring” without meaning they consider them socially lower?). Age is very important, if you treat someone older than you as someone younger, then you convey the message that they do not have the higher amount of life experience that would make them deserving of more respect than you (it’s the social construct that is the core of human interactions in Korea). But even if it marks a strong lack of respect, it doesn’t translate to “bastard”, which has a very specific meaning (someone who was born out of wedlock) that has nothing to do with the Korean jassik no matter how you put it. I like using “buffoon” a lot, but here again it doesn’t fit everywhere. I almost never use swear words in English, so now I’m trying to be very careful because I am not good at evaluating the offensive power of a swear word. I think it’s on one of irmar’s document that I saw an interesting list of insults with their meanings, and I’ve been using it whenever I’m trying to find something appropriate. But the tricky part is to use a word that doesn’t make it comical when it’s not intended, and a lot of lesser used swear words in English have that comical feel to it (exactly because they aren’t much used).
At some point, I wondered if we should maybe start translating these expressions literally. That way, there is no mildly dubious interpretation involved, and we can gauge the insulting power depending on the context and the reaction of others. But I’m not too sure how that would work, because putting “offspring” every time we hear jassik seems more comical than anything… In the case of gaejassik, though, for once I thought that s.o.b. was fitting (again, depending on the situation) since “bitch” is a female dog. But it’s true that most people don’t really use the word that way actually.
Something that also exists everywhere in the world is the use of modifiers to downplay the insult: for example, putting “little” in front of any insulting word suddenly turns it into a less harsh word and even sometimes a form of endearment (which I find appalling, but that’s another topic). On the other hand, adding “bloody” or “total” to an insult makes it stronger: no need to use a more offensive word that isn’t the accurate meaning.
Weeell haha, I’m on my way to write an essay here, oops. But we need to realize that the use of vulgar words in our subtitles are not always appropriate nor accurate, and this is such an interesting topic to discuss.