Sihwa didn't watch Korean dramas for no reason. At the very least, she was able to recognize some Korean characters. Even if she didn't know the word, she was able to understand that the word was Korean. After all, Korean characters were very distinctive; they were easily recognizable, just like the characters from both the Chinese and Japanese language.
In the past, Zhang Zian had told her that the area in Northeast Asia that was mainly doing the whaling was South Korea and Japan. The only difference was that South Korea had been doing it secretly, claiming that the whales were caught by mistake, while Japan had been blatantly killing them under the claims of it being for scientific research. Both countries had a tradition of eating whale meat. Whale meat was more expensive in its domestic market, and many people were willing to pay for the experience.