Years ago, I became interested in aUI ("The Language of Space"), mainly for its high weirdness value. I didn't make any effort to learn it but I did buy the book (This was pre-Internet) and read it with interest. aUI is a philosophical language project, almost certainly useless as an IAL but still great fun. Weilgart was a pretty interesting character.

I also find the Sona project very interesting, as a more non-Western approach--but created by an Englishman.

That aUI made me go "... bhWAWA?!!!". That said, after getting past the, erm, quirks, it is a pretty neat idea.

Some things despite their alleged alien origin are clearly not alien in nature though - that said, if they are I'll be pleasantly surprised and no doubt there'll be much for future generations to study about convergent evolution!