Imaginary languages are now par for the course in fantasy literature: sometimes called something like 'the old tongue' or 'the ancient language', sometimes the languages of different types of being...
In the answers, 'A Princess of Mars' is said to precede Tolkien. However, according to Wikipedia it was published in 1917. About the same time Tolkien produced his first version of the later Silmarillion, he just couldn't get it published throughout his whole life.
Tamas Ferencz Jan 06, 2015 (09:06)
EDIT: I see now someone actually mentions Swift in a response to the question.
Roman Rausch Jan 06, 2015 (15:09)