Slovak is a West-Slavic language, mainly spoken in Slovakia, which has been an independent country after the "Velvet Divorce" with Czech in January 1, 1993.
Not only the historically political connection with Czech, but the language of Slovak is also very closed to the language of Czech. They are highly mutually intelligible.It is also very closed to Polish.
IU offers multiple slavic language courses, including Czech and Polish but not Slovak. CeLT has some offline learning material in the recording archive.