In Tolkien’s The Lord of the Rings, what language appears in the Ring inscription?

The inscription on the One Ring is written in the Black Speech of Mordor.

The inscription contains the famous lines “One Ring to rule them all” and “One Ring to find them,” followed by lines about bringing and binding the other Rings. In the story, the words become visible when the Ring is heated, revealing fiery lettering.

Tolkien created the Black Speech for Sauron and his servants. The language is associated with Mordor and was designed to contrast with the Elvish languages, although Tolkien provided far less complete vocabulary and grammar for it than for Quenya or Sindarin.

The inscription is often mistakenly identified as Elvish because its letters are commonly shown in Tengwar, the writing system used in the films and many illustrations. Tengwar is a script, not a language. The language of the inscription is Black Speech, while the script used to display it is a form of Tengwar.