This essay examines the grammar variation of English as a common tongue of two characters from the TV series, Game of Thrones. Scenes from season 1-7 of the series where the characters Irri and Grey Worm spoke the common tongue, English, were transcribed and examined using the concepts of interlanguage (IL) and English as a lingua franca (ELF) as analytic frameworks. The two research questions for this essay are ‘What is grammatical variation of English as a common tongue spoken by two characters, Irri and Grey Worm in the TV series, Game of Thrones?’ and ‘What dramatic effects are perceived with the characters' grammatical variation in the series?’. The results showed that while both characters have features explained by both the IL and ELF frameworks, IL was a more appropriate concept for understanding the data overall. Nevertheless, Irri proved to use more ELF features than Grey Worm in the collected data in which there were more variations by Grey Worm than by Irri. In addition, three dramatic effects of the characters’ grammar variation emerged, namely emotional effect, cultural effect, and development effect. Based on the results, this essay concluded that the characters of Irri and Grey Worm had grammar variations that featured in both IL and ELF, with the majority of them being IL.