A person who has created one or more auxlangs (short for "International Auxiliary Languages", a.k.a. IALs). languages created in order to facilitate international communication.
Short for "International Auxiliary Language". a language created by a person or a group with the purpose of facilitating international communication. Typically, auxlangs are simple, regular and try to be culturally neutral. Well-known examples include Esperanto, Interlingua and Volapük.
People often measure the success of conlangs by their number of speakers, but that criterion works only for auxlangs, really.