J.R.R. Tolkien created the fictional script called Tengwar for writing several of his invented languages.
Tengwar is an abugida-style writing system developed within Tolkien’s mythology by the Elf Fëanor. It could represent languages including Quenya and Sindarin, although its letter values and spelling conventions changed depending on the language and mode being used.
The script appears in Tolkien’s books and illustrations, most famously in the inscription on the One Ring. That inscription is written in Tengwar characters, but the language itself is the Black Speech of Mordor. This distinction is a common source of confusion: Tengwar is the writing system, while Black Speech is the language of the inscription.
Tolkien developed several scripts rather than one universal alphabet. Cirth is another important system, associated especially with runic-style inscriptions and the Dwarves. His interest in writing systems reflected his broader lifelong fascination with historical linguistics, calligraphy, and the relationship between language, sound, and script.