X-languages
The X-languages are experimental languages by Jörg Rhiemeier. They are called this way because they are designated by the letter "X" followed by a number. The "X" stands for "eXperimental language".
The X-languages are quite different from each other and do not form a unified family of any sort. They surely aren't cognate in the historical linguistic sense as, for example, Low Elvish and Macaronesian are cognate. Nevertheless, there are a few recurrent features, such as self-segregating morphology and only one single open word class lumping together all the content words (nouns, verbs, adjectives etc.). None of the X-languages has a conculture attached, and none is intended to be naturalist.
What I am not going to do is to propose any of the X-languages as an auxlang or anything like that. They are experimental and way too bizarre to be actually used (for example, I doubt that any human can parse an X-2 sentence which makes ample use of the language's stack-manipulation tricks in real time); and I am doing this (as all of my conlangs) just for fun .