In The Lord of the Rings film trilogy, what is the name of the language used in the Ring inscription?

In The Lord of the Rings film trilogy, the Ring inscription uses the Black Speech of Mordor.

The inscription begins, “Ash nazg durbatulûk,” and describes one Ring ruling the others. Sauron devised the Black Speech for the servants of Mordor, making it an especially fitting language for the inscription on the One Ring. The words become visible when the Ring is heated.

Quenya and Sindarin are important Elvish languages, but neither is used for the Ring’s inscription. Westron is the common tongue of many peoples in the story. The film’s spoken Black Speech was developed for the production with linguistic guidance based on Tolkien’s invented language.