Specifically, I want Korean (link), but I hope this helps other people in general. According to this page, it is only possible for Ultimate and Enterprise. Specifically, I'd like to enable my keyboard to type in Korean, and I specified Korean as the input language (Start - type "Input Languages", only result). Under the General tab, I selected Add, and specified Korean.. but it doesn't work, because the language pack isn't installed I presume. Would anyone know how to add different language input / packs to Windows 7 Home Premium?
Also, I tried following this tutorial on adding a language pack to HP, but the .cab keeps disappearing so it will not work.
Note: Unlike the link in the tutorial as well, I do not have an option to change the display language of Windows, only the option to change input methods.