Goal of the thesis is to create educational PC application that will generate tests for user to solve. Test tasks are to be generated based on the content of small part of dictionary material of still not published Croatian words formation dictionary. Application implements two ways of using and expanding knowledge about diminutives and augmentatives in Croatian language in a form of 2D PC game. Application's look and user interface are colorful and animated in order to be more cheerful and attractable, especially to elementary school students. Some optional game sound effects and background music is integrated into the application. One type of game enables player to ask for help in solving tasks and show final solutions. Following the end of every test solving, user is presented with generated and summarized report of test results which show him all the task he has been given to solve during the game (test). Every shown task in the test results has marked parts of solution that user solved correctly and parts that user did not successfully solve. This enables users not versed in word formation processes in Croatian language to also enjoy playing this educational application and gain that knowledge they lack. Application is not rich in its content but paves the way to more complete software tool implementation which will improve learning process and better usage of Croatian language for all its users. More complicated details of word formation processes were temporary neglected during development of this application. Chosen and processed parts of formation process of diminutives and augmentatives increase Croatian language speaker's learning success, awareness and words usage.