There are the language of Wookiees, Furbies, Ewoks, and of course, John Malkovich from Being John Malkovich.
Of course, Sindarin has the greatest advantage as it’s not only been around the longest, but was crafted by Tolkien himself.
The video tackles Dothraki and High Valyrian from Game of Thrones, Parseltongue from Harry Potter, Klingon from Star Trek, Sindarin from Lord of the Rings, and Na’vi from Avatar.
You also realize that Zoe Saldana is used to speaking two fictional languages thanks to her dual roles on Avatar and Star Trek.