The Spelling City game-based language learning program allows users to use customized word lists and has a library of 50,000 words and 60,000 sentences read by an actual person, among other features. The company that publishes the software claims it has over five million users worldwide.
Students are able to use any word list, which integrates with the software's learning activities and games. Assessments can also be based on these custom word lists. The software also correlates to common educational standards such as Common Core. Users can access the software online through a Web browser or through an app that is available for most mobile operating systems.