TYK (the acronym for Teach Yourself Korean) is a generic tool for practicing vocabulary and grammar of foreign languages, primarily written to aid me in my korean studies. However, TYK will be written with extensibility in mind, in order to use it for other languages and exercises too.
To accomplish this, TYK is seperated into multiple layers. The main application is a simple browser to chose exercises from the languages and lessons that are available. Excercises themselves are written as dynamic modules, to make TYK easily extensible. The actual data for exercises is provided in XML format, making creation of new lessons and/or exercises as simple as possible.
Note however, that TYK is no complete language course. Its focus is entirely on practicing vocabulary and grammar. Nothing will be explained to you. So you will need other resources to get an initial understanding of the new language you want to learn. Afterwards, you can use TYK to test and improve your skills.