Luminarian language is a deliberate creation, presumably of their dead god. It has a certain degree of simplicity and predictability that can be expected from artificial creation, though it has many glitches indicating that their deity wasn't a particularly talented linguist.
Luminarian language uses fifteen consonants (b, d, f, g, h, k, l, m, n, p, r, s, t, v, z) and five vowels (a, e, i, o, u). The basic unit of language is a syllable always composed of one consonant and one vowel, in that order. The classic luminarian vowels are always short, though certain dialects differ by length of pronunciation. There is no deliberate accent used—in fact classic luminarian speech is sometimes described as bland and toneless by foreign speakers, with stress and non-verbal components conveyed by deliberate gestures.
There are three fixed lengths of luminarian words. One-syllable words represent classes of entities (eg. ro refers to reptilian, ve arthropods, ta stone, za fire, sa light, su mind, etheric, tu personified, anthropomorphic). Majority of common words are composed of two syllables (kala pack predator or scavenger, kamo apex solitary predator, tava dirth, earth, sula can be translated as social life or mental grouping). Full names are composed of three syllable personal name, followed by a single syllable referring to one's regional group (which have assigned class syllables, so one can come from ro, "reptile region" or ta "earth region"), followed by three syllable family name. There is a specific name for the luminarian world, manata. It is used sometimes in place of family name, together with class name -tu- as polite way of declining to reveal one's lineage.
Luminarian language uses lots of compound words as nouns, usually composed of the initial class-word followed by other words describing the subject, for example ro-kala-tava means "reptilian pack hunter (living in) earth" and refers to a specific animal species; ku-sumo-manata is "dead individuality of Manata", the luminarian creator deity, and was know as tu-sumo while alive; tu-sula originally meant luminars themselves and now is general reference to sapient, more or less humanoid people (though lizardmen would be ro-sula instead), tu-sula-tava means "people of earth" and was coined after the first contact with dwarves. Now, when luminars need to distinguish themselves from other sapient people, they call themselves tu-sula-manata, "people of Manata".
While there are currently around sixty types in use, luminarian philosophers are concerned about possibility of existence of more types, exceeding the inherent limitation of having only seventy five syllables in their language. There are obvious connections between many classes and related words (roda scale, veda chitin, plate, suda psychic aura), though many other words seem like arbitrary picks made by the dead deity (or the philosophers and linguists for words introduced after the deity's death). There is no distinction between singular or plural forms, but it is customary (though not required) to provide a non-verbal cue. A closed fist represent singe being, an open palm plural, while having one or more fingers extended usually representing specific number, up to four, or orders of magnitude when the context already conveys a significant number. However certain words imply uniqueness or solitude, such as kamo "apex predator" is expected to be solitary as opposed to kala "pack predator". Luminarian language has no homophones and generally lacks synonyms, at least when it comes to common words, though there are different compound words referring to the same specific subjects, especially the many compound words referring to the luminarian deity. In fact, luminars learning alien languages find both concept particularly hard to comprehend. On the other hand, the exact meaning of common words can be hard to translate as they might refer to wide phenomena, for example sula is sort of general term for social life/ Together with humanoid class it forms tu-sula, people, with mental class it is su-sula, the abstract concept of culture, and with the arthropodic class it becomes ve-sula, the hive. Many words also function as nouns, verbs, and possibly adjectives, depending upon context and position in the compound word, for example kala could mean hunt, while kamo is solitary hunting or killing.
Non-verbal cues used by luminarian language are rather pronounced and far from subtle, using primarily hand gestures—luminarian faces are not particularly expressive, nor are luminars keen on noticing subtle social hints. The gestures most commonly used used by luminars include covering one's mouth when speaking frivolously or in jest, merely brushing one's lips with finger to imply humorous aspect to the statement, speaking serious things one does not believe involves covering one's eyes, and touching one's temple when speaking things from memory notes possibility of less than perfect recall. If luminar actually doubts his memories he will be touching his forehead instead, with the exact placement of the hand between temple and the forehead being declaration of degree of uncertainty.