Choosing the proper languages/frameworks/tools based on countries?

It's obvious that programming languages, web frameworks can be ranked based on some facts, such as, year, country, or type of position(back-end, front-end, data science etc). What I want to know is that how can I know the right and marketable programming languages/frameworks/tools based on South Korean market? In other words, how I can get a job very quickly having (Java/Python/JavaScript) or something in South Korea?

Thanks in advance!