The Orcs’ invented language in The Lord of the Rings is called the Black Speech.
Tolkien created the Black Speech as the language devised by Sauron for the servants of Mordor. It appears most prominently in the inscription on the One Ring: “One Ring to rule them all, One Ring to find them.” The inscription is written in Tengwar script, but the language itself is the Black Speech.
The Black Speech should not be confused with Sindarin or Quenya, which are Elvish languages. Westron is the Common Speech used widely by the peoples of Middle-earth, while Valarin belongs to the Valar. These distinctions matter because Tolkien’s fictional languages are connected to different peoples, histories, and regions.
Tolkien did not develop the Black Speech as extensively as some Elvish languages. The surviving examples are therefore limited, but the language’s role is clear: it represents Sauron’s attempt to impose a linguistic unity on the forces of darkness.