Don't know your chifthik from your choyo? Take a language lesson as David J Peterson explains how he created the Dothraki language for Game of Thrones and Irathient and Castithan for Defiance . Get pronunciation tips, advice on how to wound your enemy with a cutting insult and a guide to making made-up languages sound authentic: Season 2 is available on Blu-ray and DVD nowcan be seen Tuesdays at 9pm on Syfy