https://www.cnet.com/news/learn-game-of-thrones-language-high-valyrian-in-5-easy-steps/

What started as a few phrases in George R.R. Martin's books are now fully built-out languages thanks to Peterson's work. High Valyrian, which is a bit like an ancient Latin for the Seven Kingdoms, now has more than 2,000 words with real rules and structure. So how can you make folks believe Valyrian is your mother tongue? Peterson offers a few points of guidance below -- along with some phrases you can use in your everyday life:

"Roll every 'R' you see," says Peterson. "Every single one. Roll it extra. That's going to give you a nice Valyrian accent. Other than that, it's just intonation."