If you want to pick up a new language in a short amount of time, you may want to start with Portuguese instead of Korean.
According to the Foreign Service Institute (FSI), a native English speaker would need around 24 weeks to learn the former. To learn the latter, however, the speaker would need to study the language for more than a year and a half, or about 88 weeks.
Based on their experience training US diplomats, the FSI divided all the languages they teach into four distinct categories. The higher the category, the more classroom hours a student would need to reach a "general professional proficiency" in both speaking and reading the language. Or, in simplest terms, the higher the category, the "harder" the language is to learn for a native English speaker.
Dark yellow (Category IV): On the map, Category IV languages correspond to the FSI's official Category III languages. These are "hard languages" with "significant linguistic and/or cultural differences from English" that require around 44 weeks of full-time study to reach proficiency.
Examples of Category III (or Category IV on the map) languages include Hindi, Hebrew, Greek, Farsi, Russian, and Czech.