Short for "constructed language". A language that does not occur by natural process and is not a normal product of a national culture, but is invented either for personal/private use, fiction (Klingon, Tolkien's Quenya), international communication (Esperanto), political reasons, or as an experiment.
Esperanto, a conlang designed for simple communication between differing language groups, especially European, has millions of speakers, though its exact number is uncertain.
A language that has been constructed, such as Klingon or Esperanto.
His hobbies include making conlangs.