Publisher Random House has launched a language app to promote the fantasy series Game of Thrones. The app teaches users how to speak Dothraki, one of the fictional languages found in the book series and on the popular HBO adaptation.

The app, which is available on iOS, is based on the work of linguist David J. Peterson, who worked with author George R.R. Martin to develop a basic language that could be used on the Game of Thrones show, based on phrases found in the A Song of Ice and Fire book series.

The book series and show both have a passionate fanbase who had already catalogued much of the information on Dothraki culture and language in online communities, but this represents the first official guide to the language, and includes material developed exclusively for the language course.

The app, produced with Living Language, functions like traditional language apps, providing vocabulary, pronunciation guidance, grammar tips and dialogue. The app also includes flash cards, games and tools to help people memorise the language, as well as information on the culture of the Dothraki.

“Im thrilled to be working with Living Language to produce the first official Dothraki text,” said Peterson. “This book will take you from arakh to zhavvorsa in no time, and the audio samples will help you perfect your pronunciation.”