A collaborative language, collablang or colllang (with triple l to avoid confusion with “conlang”) is a language constructed by a team of two or more people. Colllangs are the conlang analogy to colworlds in world-building.
Historically, most colllangs have lasted only a few months before being abandoned by most of their collaborators. Some continue as solo projects with occasional contributions from others. Gary Shannon wrote an article for Fiat Lingua "Is a Collaborative Conlang Even Possible?" on this subject.