From Sapir to Worf: Experimental Languages
Experimental languages are both the most excessive form of conlang and the most excusable, because an experimental language often provides the novum of the story in which it appears. Usually this has something to do with the Sapir-Whorf hypothesis: the idea that language influences thought, so that different language speakers think differently in some sense. At the least, an experimental language reflects some unusual linguistic possibilities.
Klingon, constructed by linguist Marc Okrand for use in several Star Trek movies, is an agglutinative experimental language which flouts various near-universals (of word order and phonology) and takes the most alien path whenever possible. You can watch his talk about constructing Klingon on YouTube.
Marc Okrand also invented the Atlantean Ur-language for a Disney film. The concerns of writers are somewhat different than those of screenwriters, who can afford to hire a linguist for the atmosphere, so this chapter will focus on experimental languages that have appeared in books.