the second most successful invented language is called Klingon.Other than the fact that it is also an invented language, it shares almost no similarities with Esperanto. Klingon, which was invented only 25 years ago, was not created with the noble intention of promoting the peaceful coexistence of people from different cultures. Instead, it is a trademarked invention of a major movie studio. It was created in 1984 by a linguist named Marc Okrand for use in the Star Trek movies. The characters who speak this language are the Klingon, a fictitious race of people from outer space.