J.R.R. Tolkien created many languages throughout his life. He wrote in one of his letters that the tales of Middle-earth (The Hobbit, The Lord of the Rings and The Silmarilion) grew from these languages, rather than the languages being created for use in the stories.
Tolkien also created a number of different alphabets to write his languages - he modelled Cirth on Anglo-Saxon and Norse Runes. Its function in his stories is for inscriptions in wood and stone, just as Runes were used in the real world.
A number of different languages of Middle-Earth, such as:
Quenya (Qenya or High-elven), the most prominent language of the Amanya branch of the Elvish language family. Tolkien complied the "Qenya Lexicon", his first list of Elvish words, in 1915 at the age of 23 and continued to refine the language throughout his life. It is based mainly on Finnish, but also partly on Greek and partly on Latin.
Sindarin, the language of the Grey-elves or Sindar. Tolkien based Sindarin on Welsh and originally called it gnomish.
Dwarvish, the language of the dwarves.
Klingon mode for Cirth, by Yehuda Ronen
http://my.ort.org.il/tolkien/gandalf/html/klicirth/klicirth.html
More links to sites about Tolkien's alphabets and languages
Cirth, Sarati, Tengwar, Uruk Runes
Ancients' Alphabet, Ath, Atlantean, Aurek-Besh, Cirth, Daedric, D'ni, Dragon Runes, Futurama Alien Alphabet, Gargish, Gnommish, Golic Vulcan, Hylian syllabary (Old), Hylian syllabary (Modern), Hylian alphabet, Klingon, Kryptonian, Marain, Matoran, Romulan, Sarati, Standard Galactic Alphabet, Tsolyáni (Tékumel), Tenctonese, Tengwar, Utopian, Visitor, Zentlardy