J.R.R. Tolkien based Quenya partly on Finnish, while adapting it into an Elvish language for his mythology.
Quenya is one of Tolkien’s best-developed languages and is associated especially with the Noldor and other high Elves. Its sound patterns and grammar reflect Tolkien’s interests in historical linguistics, and Finnish provided an important inspiration for its structure and appearance.
Quenya is not the same as Sindarin, another major Elvish language in Tolkien’s legendarium. Sindarin was influenced strongly by Welsh and became the more commonly spoken Elvish language in much of Middle-earth during the Third Age.
Tolkien did not invent Quenya as a simple code for translating English words. He developed vocabulary, grammatical rules, sound changes, and historical relationships between languages, treating them as parts of a broader fictional linguistic history.