Chi Luu writes for JSTOR Daily on the popularity of invented languages, ranging from the mystical language created by a 12th century abbess to contemporary constructed languages such as Esperanto and Klingon.

Invented languages found in literature are really examples of linguistic artistry, language for art’s sake, not necessarily for real world utility or universality…. readers can often be exposed to other world viewpoints and play with ideas in that universe—linguistic relativity in space so to speak.