The Glossopoeia
The term glossopoeia was coined by J. R. R. Tolkien. It is used today to mean language construction, particularly construction of artistic languages.
Tolkien's glossopoeia has two temporal dimensions: the internal (fictional) timeline of events described in the Silmarillion and other writings, and the external timeline of Tolkien's own life during which he continually revised and refined his languages and their fictional history.
He was a professional philologist of ancient Germanic languages, specialising in Old English. He was also interested in many languages outside his field, and developed a particular love for the Finnish language. He described the finding of a Finnish grammar book as "entering a complete wine-cellar filled with bottles of an amazing wine of a kind and flavour never tasted before".
Glossopoeia was Tolkien's hobby for most of his life. At a little over thirteen he helped construct a sound substitution cypher known as Nevbosh, 'new nonsense', which grew to include some elements of actual invented language. Notably, Tolkien claimed that this was not his first effort in invented languages. Shortly thereafter he developed a true invented language called Naffarin which contained elements that would survive into his later languages, which he continued to work on until his death more than sixty-five years later. Language invention had always been tightly connected to the mythology that Tolkien developed, as he found that a language could not be complete without the history of the people who spoke it, just as these people could never be fully realistic if imagined only through the English language and as speaking English. Tolkien therefore took the stance of a translator and adaptor rather than that of the original author of his works.
In the Lord of the Rings, he adopted the literary device of claiming to have translated the original Sôval Phârë speech (or Westron as he called it) into English. This device of rendering an imaginary language with a real one was carried further, rendering Rohirric the language of Rohan, related to Sôval Phâre, by Old English, and names in the tongue of Dale by Old Norse forms, and names of the Kingdom of Rhovanion by Gothic forms, thus mapping the genetic relation of his fictional languages on the existing historical relations of the Germanic languages. Furthermore, to parallel the Celtic substratum in England, he used Old Welsh names to render the Dunlendish names of Buckland Hobbits (e.g., Meriadoc for Kalimac). A natural consequence of this was that these "new" constructed languages had to be worked out by Tolkien in some details.
Although the Elvish languages Sindarin and Quenya are the most famous and the most developed of the languages that Tolkien invented for his Secondary World, they are by no means the only ones. They belong to a family of Elvish languages, that originate in Common Eldarin, the language common to all Eldar, which in turn originates in Primitive Quendian, the common root of Eldarin and Avarin languages. In addition to that, there is a separate language family that is spoken by Men, the most prominent member of which was Westron (derived from the Númenórean speech Adûnaic), the "Common speech" of the peoples of The Lord of the Rings. Most Mannish tongues showed influences by Elvish, as well as some Dwarvish influences. Several independent languages were drafted as well, an example being Khuzdul, the language of the Dwarves. Other languages are Valarin (the tongue of the Valar), and the Black Speech created by Sauron in the Second Age.
Finnish morphology (particularly its rich system of inflection) in part gave rise to Quenya. Another of Tolkien's favourites was Welsh, and features of Welsh phonology found their way into Sindarin. Very few words were borrowed from existing languages, so that attempts to match a source to a particular Elvish word or name in works published during his lifetime are often very dubious.
Read more about this topic: Languages Constructed By J. R. R. Tolkien