There have been a number of language creators over the years who have tackled some "ironclad" linguistic universals head on. For example:
- Kēlen by Sylvia Sotomayor
- Kēlen (interview) has no verbs. Instead, it has a closed class of four "relationals" which describe states and events in a very broad fashion: existence, change, transaction, or containment.
- Dritok by Donald Boozer
- Dritok (video) is a mixed spoken/signed language - to pronounce some words, one must speak and sign simultaneously. In addition, its spoken component has no voiced sounds (e.g. all vowels in English).
- Fith by Jeffrey Henning
- Fith syntax is based on a stack, permitting operations with no human analogue and which humans probably can't learn, such as scrambling the stack in the middle of a sentence, or splitting a sentence in half and putting a whole paragraph in the middle.
- Disharmony by Amanda Furrow
- Disharmony is a sketch of an unsingable musical language with center-embedding (another syntax probably impossible for humans).
There are more conlangs which are not specifically intended to violate universals, but which happen to have done so in the process of pursuing their a priori goals:
- Ithkuil by John Quijada
- Ithkuil's highly complex morphology allows one to express a tremendous amount of information in a very compact form.
- Lojban by James Cooke Brown and the Logical Language Group
- Lojban's grammar is based on predicate logic and designed to be extremely precise (including about emotions), culturally neutral, and computer parseable.
- gjâ-zym-byn by Jim Henry
- gjâ-zym-byn's author has gained some degree of fluency in it despite its severely unusual characteristics.