The muse possessed me last week, churned out all of these in the space of a day.
I just think they're neat!
Adûnaic (J.R.R. Tolkien)
John was holding out on us and it's a damn shame. This one's got some A E S T H E T I C. Love me a good û. Westron itself also gets bundled here, gotta give out a shoutout to my man Banazîr Galbasi. I feel like it should be mentioned that, in the work considered the poster child of Euro-fantasy, nearly all of the characters are speaking something explicitly modeled on Semitic and Mesopotamian languages. No Greek or Latin to be seen. That seems like something a lot of people miss.
Toki Pona (Sonja Lang)
Can't get into it. The limited phonology, limited vocabulary, short word length, extreme isolating grammar, and lack of compounding make it so repetitive visually and aurally that it dissolves into white noise for me. The many Tokiponidos out there hacking the language into even smaller wordlists and phonologies strike me as bizarre - there is a limit to how minimalist you can get before information transfer breaks down. Jonathan Gabel's sitelen sitelen is easily one of my favorite scripts for anything, though, gold star on the Good Noodle Board.
Toki Ma (Shevek Urrasti)
The vocabulary and grammar have been expanded into something more robust, which is nice. Close enough for petanque. Many of the (enormous) lexical gaps of Toki Pona have been filled. The limited phonology is much less of an issue, as the extended vocabulary makes things much less repetitive. A marked improvement (sans the loss of sitelen sitelen) if outside the philosophical bounds of Toki Pona. (NOTE: The main website for the language appears to be down and is being squatted by a phishing scam.)
Ithkuil (John Quijada)
A masterpiece of outsider art. The impracticality of actually using it and the headaches I get when I try to read through it are nothing compared to the fact that Quijada has a vision, and he has been chipping away at that marble block for nearly 20 years, and damn any outside expectations of what it can or should be. 20 years, expanding and refining and improving this thing that, I suspect, makes full sense only of Quijada himself. And that's beautiful to see. Hurts my head to consider, but I keep coming back to think about it.
Globasa (Hector Ortega)
As a rule, I find International Auxillary Languages a rather dull genre. They trend towards sameness - looking the same, sounding the same, keeping the same grammar and chasing the same fever-dream of "maybe this time, it will work!" That aside, Globasa is probably my favorite in the genre. It has a helpful website, the creator has explicitly released it into the public domain, and generally it has done enough well and avoided enough pitfalls to fill the one slot I have for positive IAL opinions.
Lojban (Logical Language Group)
As with most attempts to use an algorithm to fulfill a creative endeavor, the end result is an ugly mess. That and I'm philosophically opposed to internet rationalism and doubly so against a conlang explicitly designed to prevent puns.
Na'vi (Paul Frommer)
The language is fine. Whatever. One of those high production high polish made-to-order big media conlangs. The context around the language is the sort of bullshit that makes me want to take this entire hobby and dump it into the fucking sea. The absolute fucking...gods can you imagine what you could do with that much money if, instead of dumping it down the black hole of Cameron's ego, you, I don't know, invested it in actual environmental stewardship or language revitalization programs? He didn't even have the fucking decency to make good movies! God damn it!
Klingon (Mac Okrand)
I love Klingon. I love its ugliness, its jankiness, it's weird regularity and odd limitations. It's like seeing a dinosaur in full, majestic plumage - master of an era long since passed. It's weird and idiosyncratic and awkward and the linguistic equivalent of an incredibly ugly dog who's just the sweetest and best boy you've ever seen. No shade to David Peterson, but his output is of a consistent high competence that leaves me without much to say. Of course jank is not always good, and Klingon suffers from the "they use <x> and <q> so they must be warlike" coding that is extremely tiresome. This part I do not love. Also the script is terrible.
Kala (Carl Buck)
I love Kala. Aesthetically pleasing both in romanization and custom script, robust-enough grammar that is still pretty easy to grasp. It's not particularly complicated or out there, but it doesn't need to be. Fulfills a niche that i happen to like.
Sambhasa (Olivier Simon)
A Proto-Indo-European inspired IAL that makes the choice to keep modern spellings of words to maintain familiarity, which leads to an incredibly complicated system of phonological / pronunciation rules to follow and a sinking suspicion that you might as well just use English.
Dothraki (David J. Peterson)
Like Na'vi, the language is Fine. I don't care for it, in large part for reasons unconnected to the language itself - the Dothraki are the great modern exemplar of ACOUP's so deftly-named "barbarian couture", and so we end up with a Fine language paired with the portrayal of a people as filthy, violent, artless, possessing no culture beyond "horse" and "fight", and altogether Other. They use <x> and <q> so you know they're savages /s.
If I had a nickel for every conlang made for a major media IP whose existence is predicated on perpetuating racist stereotypes, I would have fifteen cents. Which isn't much but it's indicative of a pattern. Could get a full quarter if I added the conlangs written by out-and-out white supremacists.
Ido, Neo, Interlingua, Lingua Franca Nova, Et Cetera
At last, conlangs willing to ask the daring question of "What if French, but also Spanish and / or Italian?"
Asa'pili (Hans Widmer)
It's really just a short wordlist instead of a language, but I think it's neat as a little exercise in utopian thought - that wordlist plots out the broad brush painting of a society.
Esperanto (L.L. Zamenhof)
I am obligated to mention Esperanto here. My opinion is thus: it is historically important, a bad conlang in a a few mildly interesting ways, and ultimately irrelevant to me.
I love the script, love how frustrating/absurd the in-setting lack of spelling reform is. And, has been previously established, I love any conlang that sounds like Enheduanna is about to start singing hymns in it. Why? Not a clue. Guess I just like Gilgamesh vibes - ill-defined as that is.
Siwa (Etienne L. Poisson)
I'll be honest I have barely looked into this one, on the grounds that the grammar is 739 pages long and incredibly thorough. But hot damn has it got a slickly-designed and thorough grammar document.
Belter Creole (Nick Farmer)
Confession time: I don't like the The Expanse. I like parts of The Expanse, and this is one of them - it offers a welcome dose of cultural flavor to a setting I find dominated by the plain skinless chicken breast elements of sci-fi (grumbles in space-grognard) Unlike a lot of future-slang deals, Belt Creole feels like a natural component of life in the setting, rather than just some randomly-assembled words shoved into English.
Old Daevite (LongLangLin)
Love the Daevites, one of my all-time favorite things to come out of the SCP wiki. It's a solid base grammar, and includes some fun stuff like stop mutation types according to social class, a custom script, and a truly weird numerical system used by the upper classes (Base 7, but the first 7 digits are limited to prime numbers 2-17 and anything non-prime is just a combination of prime components. There's no numeral for 1). Plenty of footnotes, as is right and good. The first word in the noun list is "human sacrifice" which, yeah, checks out for the Daevites. On the whole, a good crossover between conlangs and the stories of the wiki.
Ämärangnä Language (Adytite) (User Deleted)
Another SCP conlang, this one regarding a Siberian language of the old Sarkic cults. Different tack from Daevite, as this one is focused primarily on the conlang's position as a fictional descendent of Proto-Uralic. There's a much greater focus on sound changes and compared vocabulary than in Old Daevite. I know significantly less about the Sarkics (after my time) so the connections to the greater setting pass me by. There is a sizable error / oversight in the noun section, where it says that there are 14 classes, but then only lists three. As with Old Daevite, this is mostly a sketch, as it too is serving dual purposes (conlang, but also a tale).
Sahrian (Greg Kasavin)
Despite how little detail we have, I think that Sahrian is one of the best examples of what a conlang can do, despite avoiding most of the things that are associated with the medium. The lexicon is small, limited to voice clips that rarely reflect what is actually being said. There's no released grammar or wordlist (Greg mentioned a spreadsheet he kept of all the words and phrases with their English equivalents, but never got around to sharing it. Fan reconstructions have not gone far. Ah, pipe dreams.) So for the player, Sahrian is a thing of recognizing words and filling in their meaning from tone, delivery, and context. It's an excellent example of how a conlang can function as a component of a larger work: it gives flavor and depth to the setting and characters, without becoming a stumbling block that players have to muddle through to get anything out of it. There's an incredible amount of meaningful variety underneath - dialect variants between characters, archaisms, speech impediments, little personal quirks. Jodariel uses formal speech. Falcon Ron has a speech impediment. Sir Gilman uses archaisms. Pametha always uses the affectionate form when speaking to you. All combined, the effect is remarkable, and probably my favorite of the entire lot reviewed here. The folks at Supergiant went A & B the C of D, and that ought not go unappreciated. Noxalas!