Conlangs have tiny communities so it's hard to make definite statements about popularity. Other than Esperanto, Interlingua, and some fictional languages, ther

Conlangs have tiny communities so it's hard to make definite statements about popularity. Other than Esperanto, Interlingua, and some fictional languages, there's pretty much just Lojban and Toki Pona, neither of which are at all based on Indo-European languages.