I think that approach might walk you into the domain of philosophical languages. In order to subdivide the space you need to establish boundaries, which then must become explicit vowels. Any variability is then merely allophony that can be mapped to real phonemes, and the whole point of it is lost. The phonetic realization might be within any arbitrary, non-overlapping subdivision of the possible vowel space, but those still can (and must) be labelled for communication to be meaningful. Like with any oligosynthetic language, you'll find you run out of short words sooner than you'd like.

The original formula of using vowels as a kind of coordinate system for continuous traits (which I think was intended as a conceptual broadening of the bouba/kiki effect) is fundamentally a lot more interesting. You're right that it wouldn't be very possible/desirable to transcribe communication with exacting fidelity in an alphabet like the IPA, but you could use floating-point numbers for academic purposes, and a non-discrete scheme for a native script, such as the angle and length of a single line, or the intersection point of two lines—ideas that sometimes manifest in featural abugidas.

As to what to use these marking systems for, you're probably right that environment is key. Maybe there's a special set of adjectival morphemes, CVC, where the consonants indicate the qualities on each axis, and the vowel indicates the value. For example, "g" = size and "t" = taperedness, so "gɯt" indicates that something is big but not tapered, but "tɯg" (a synonym of "gat") means small and sharp. Insert rules about correct ordering (and the meaning of null consonants) per the chef's taste.

#394

The gender of nouns and pronouns in the sentence is relative to the gender of the verb. So if “to be” is a feminine verb, only women can say “I am” and have the statement be grammatically correct.

I'm already doing this one with Oksirapho, which is partly a radical investigation into sexism gone deeply mad. But I think I outdid the submitter: the feminine/natural verbs use an ergative syntax, literally enshrining passivity in grammar. Normally I hate Shitpost-Whorf theory but this one was too good to pass up.

#383

Create a conlang for academia, in which the unmarked form of a verb means that the action is happening in theory, and verbs receive an extra marking to indicate that they happen in practice.

Wait, isn't that how infinitives already work? Shit. I've been bad-conlanging my whole life.

#326

Screw discrete vowel systems. All possible vowel sounds are used. You can continuously vary the meaning of any word by continuously varying the vowels within it. Perhaps /kin/ means “large”, /kɒn/ means “small”, /kun/ means “tall but narrow”, /kan/ means “short but wide”, /ken/ means “large but not much taller than average”, and /kən/ means “of neutral size”.

This one's so depressingly obvious I might as well use it for Paligu. Contriving a writing system for it will be tough, though. I foresee infinite potential for language drift caused by hyperbole. Possibly with the occasional sarcastic inversion, like a planet's magnetic field?

It was Winter, in the ninety-first year of the second reign of Klito XIX (Klito the Nineteenth), when the woman arrived at the temple.

CLASSICAL ILLERAN (6th c. LILPO): Reselíat, pléovet vesalkevis il leví hakrodeklo-talo o Klitéan ʖL^evis (o Klito Mivesevis), sta ha koistillas ogelzé.

WANISINESE ILLERAN (124th c. WANPO): Reselyat, wete ple vezagev il lev halo il Klito ʖL^ev (o Klito Stavezev), ogeze godya melas kistilla.

REGENI LILITIC (4th c. TGC): Kimoite, en ninta he enevi etos il diavi basileno il to Klito ΙΘʹ (o Klito Dekaennea), gina hikanelle an Heirelias.

MODERN IMPERIAL WANISINI (124th c. WANPO): Klaregsat, lak e tangtakhev plevot il lenev Salkzeto il o Klito ƧN.ʖ^ev (o Klito Raitang e Mitev), oymor sto o tigvotikolos.

-

Linguistic family tree for the above (Archipelagian, Wanisini, and Wanisinese Illeran are all contemporary; true Illeran is many thousands of years old at this point):



(Not diagrammed: Later developments in Lilitika, history of Oksirapho, modern revivalist Illeran, or any influences from foreign languages. Most obviously, by the time of the Regeni/Reed era in Thet, most vocabulary had been replaced with Greek due to Glissia influence within academic communities. Bizarrely this is not the only Terran in the samples given: the Illeran word pléovu, "year," has been reconstructed as having an ancestor in Classical English "planet.")