If I understand what you are asking right... here is the answer -
Tolkien was not the first to use a made up language and in fact making up languages was quite common. These are just the first two examples I found, I am sure there are more out there.
In 1516 Thomas More made the Utopian language for his novel Utopia. He even gave a brief sample of this language addendum to More's book, written by his good friend Peter Giles. See:
In 1726 in A Voyage to Lilliput Jonathan Swift has the Lilliputians say various things in their own language. An example - "Lumus kelmin pesso desmar lon emposo" - "swear a peace with him and his kingdom".
Although not a truly full made up language as the details of the language was never written out.
Oxford Dictionaries blog: Invented languages.
But the act of creating languages is not alone in it's use in fiction. There has been a long history of created or constructed languages throughout history -
A legend recorded in the seventh-century Irish work Auraicept na n-Éces claims that Fénius Farsaid visited Shinar after the confusion of tongues, and he and his scholars studied the various languages for ten years, taking the best features of each to create in Bérla tóbaide ("the selected language"), which he named Goídelc — the Irish language. This appears to be the first mention of the concept of a constructed language in literature.
delc — the Irish language. This appears to be the first mention of the concept of a constructed language in literature.
The earliest non-natural languages were considered less "constructed" than "super-natural", mystical, or divinely inspired. The Lingua Ignota, recorded in the 12th century by St. Hildegard of Bingen is an example, and apparently the first entirely artificial language. It is a form of private mystical cant.
An important example from Middle-Eastern culture is Balaibalan, invented in the 16th century. Balaibalan was created in Timurid or Safavid Iran, and one of the first known constructed languages.
Its original creator may have been 14th century mystic Fazlallah Astarabadi, founder of Hurufism. But there is evidence that it might have been his followers in the 15th century, or may have even been Muhyî-i Gülşenî. There is only one example of this language, a dictionary, copies of which are to be found in the Bibliothèque nationale de France in Paris and in the Princeton University Library.
Johannes Trithemius, in Steganographia and Polygraphia, attempted to show how all languages can be reduced to one. In the 17th century, interest in magical languages was continued by the Rosicrucians and Alchemists (like John Dee and his Enochian). Jakob Boehme in 1623 spoke of a "natural language" (Natursprache) of the senses.
Musical languages from the Renaissance were tied up with mysticism, magic and alchemy, sometimes also referred to as the language of the birds. The Solresol project of 1817 re-invented the concept in a more pragmatic context.
And for interests sake, here is a list of some constructed languages from recent years:
1. Solresol created in 1827 by François Sudre : Based on pitch levels sounded with their solfege syllables (a "musical language") although no knowledge of music is required to learn it.
2. Communicationssprache created in 1839 by Joseph Schipfer : Based on French.
3. Universalglot created in 1868 by Jean Pirro : An early a posteriori language, predating even Volapük.
4. Volapük Created in 1879–1880 by Johann Martin Schleyer : First to generate international interest in IALs
5. Esperanto created in 1887 by L. L. Zamenhof : The most popular auxiliary language ever invented, including, possibly, up to two million speakers, the highest ever for a constructed language and the only one to date to have its own native speakers.
6. Spokil created in 1887 or 1890 by Adolph Nicolas : An a priori language by a former Volapük advocate.
7. Mundolinco created in 1888 by J. Braakman : The first esperantido
8. Idiom Neutral created in 1902 by Waldemar Rosenberger : A naturalistic IAL by a former advocate of Volapük.
9. Latino sine Flexione created in 1903 by Giuseppe Peano : "Latin without inflections," it replaced Idiom Neutral in 1908.
10. Ro created in 1904 by Rev. Edward Powell Foster : An a priori language using categories of knowledge.
11. Ido created in 1907 by a group of reformist Esperanto speakers : The most successful offspring of Esperanto.
12. Adjuvilo crated in 1910 by Claudius Colas : An esperantido some believe was created to cause dissent among Idoists>
13. Occidental created in 1922 by Edgar de Wahl : A sophisticated naturalistic IAL, also known as Interlingue.
14. Novial created in 1928 by Otto Jespersen : Another sophisticated naturalistic IAL by a famous Danish linguist.
15. Sona created in 1935 by Kenneth Searight : Best known attempt at universality of vocabulary.
16. Esperanto II created in 1937 by René de Saussure : Last of linguist Saussure's many esperantidos.
17. Mondial created in 1940s by Dr. Helge Heimer : Naturalistic European language.
18. Glosa created in 1943 by Lancelot Hogben : Originally called Interglossa, has a strong Greco-Latin vocabulary.
19. Blissymbols created in 1949 by Charles Bliss : An ideographic writing system, with its own grammar and syntax.
20. Interlingua created in 1951 by International Auxiliary Language Association : A major effort to develop a common Romance vocabulary.
21. Intal created in 1956 by Erich Weferling : An effort to unite the most common systems of constructed languages.
22. Romanid created in 1956 by Zoltán Magyar : A zonal constructed language based on the Romance languages.
23. Lingua sistemfrater created in 1957 by Pham Xuan Thai : Greco-Latin vocabulary with southeast Asian grammar.
24. Neo created in 1961 by Arturo Alfandari : A very terse European language
25. Babm created in 1962 by Rikichi Okamoto : Notable for using Latin letters as a syllabary.
26. Arcaicam Esperantom Created in 1969 by Manuel Halvelik : 'Archaic Esperanto', developed for use in Esperanto literature.
27. Afrihili created in 1970 by K. A. Kumi Attobrah : A pan-African language.
28. Kotava created in 1978 by Staren Fetcey : A sophisticated a priori IAL.
29. Uropi created in 1986 by Joël Landais : Based on the common Indo-European roots and the common grammatical points of the IE languages.
30. Poliespo creaed in the 1990s (?) by Nvwtohiyada Idehesdi Sequoyah Esperanto : grammar with significant Cherokee vocabulary.
31. Romániço created in 1991 by Anonymous : Vocabulary is derived from common Romance roots.
32. Europanto created in 1996 by Diego Marani : A "linguistic jest" by a European diplomat.
33. Unish created in 1996 by Language Research Institute : Sejong University Vocabulary from fifteen representative languages.
34. Lingua Franca Nova created in 1998 by C. George Boeree and others : Romance vocabulary with creole-like grammar.
35. Slovio created in 1999 by Mark Hučko : A constructed language based on the Slavic languages and Esperanto grammar.
36. Interslavic created in 2006 by Ondrej Rečnik, Gabriel Svoboda, Jan van Steenbergen and Igor Polyakov : A naturalistic language based on the Slavic languages.
37. Sambahsa-Mundialect created in 2007 by Olivier Simon : Mixture of simplified Proto-Indo-European and other languages.
38. Lingwa de planeta created in 2010 by Dmitri Ivanov : Worldlang based on Arabic, Chinese, English, French, German, Hindi, Persian, Portuguese, Russian, and Spanish.
See List of constructed languages on Wikipedia.