...I couldn’t speak English

https://www.buzzfeed.com/benhenry/jason-momoa-can-speak-english-guys

"Yeah, not a lot of people thought I spoke English. It was very challenging," Momoa tells Jimmy Fallon of his convincing Dothraki language skills. Momoa says he didn’t know about the false perception until he met Fred Armisen, who was stunned that he spoke English.