The inscription on the Doors of Durin in J.R.R. Tolkien’s The Lord of the Rings is written in Sindarin.
The Doors of Durin stand at the western entrance to Moria. Their inscription begins with the invitation “Speak, friend, and enter,” and the hidden mechanism opens when the correct Elvish word is spoken. The word is “mellon,” meaning “friend.”
The lettering is written in Tengwar, the Elvish script Tolkien designed for several languages. This creates a common mix-up: Sindarin identifies the language, while Tengwar identifies the writing system. The doors are therefore not simply “written in Tengwar” if the question asks for the language.
The inscription reflects the friendship between the Elves of Eregion and the Dwarves of Khazad-dûm. Celebrimbor is associated with the inscription, and the door was made by the Dwarf Narvi.