What is the name of the language used for the Ring-inscription in J.R.R. Tolkien’s Middle-earth?

The language used for the Ring-inscription in J.R.R. Tolkien’s Middle-earth is the Black Speech of Mordor.

The inscription on the One Ring is a verse in the Black Speech, created by Sauron for the inhabitants and servants of Mordor. Its best-known English rendering begins, “One Ring to rule them all,” and describes the Ring’s power over the other Rings of Power.

Tolkien wrote the inscription in a script associated with the Tengwar, but the writing system and the spoken language are different things. The letters are a form of writing; the Black Speech is the language being represented. This distinction can be obscured in adaptations and fan discussions.

The Black Speech is also distinct from Quenya and Sindarin, the better-known Elvish languages. Tolkien gave those languages extensive histories and vocabularies, whereas the Black Speech is presented primarily through the Ring verse and a small number of other examples.