Colour is perhaps the central concept to understand in both Classical and Modern Gluonic. Colour is the main quality that grammatical agreement acts upon in these languages, and it is necessary to delve into the concept in more detail before moving on to other areas of the grammar.

There are four colours - the "gluonic colours," blue, red, and green, generally expressed in that order due to the facts of Modern Gluonic, plus black, which is the absence of colour. The three gluonic colours correspond symbolically to the three colour charges of the strong nuclear force, an idiom that is reputed to have actually developed in the times before the Gluonic religion and culture arose in their original home dimension. Here on Earth-0001, our scientists borrowed this concept from Gluonic culture, which is why we use the same "colour charge" idiom in our physics.

There is also a "fifth colour," white, that has a certain mystical and religious significance and can influence the structure of utterances in sacred contexts, but has less influence on secular communication. Whiteness, however, is a property of entire utterances and not a true grammatical quality. It is a topic we will pick up again later, but in a nutshell, it pertains to balance between the three colours.

The Function of Colour

Colour in Gluonic works in many ways like gender in Terrestrial languages that have it, like French or German. Gender is a better comparison than the more general noun class, as we see in many languages, especially in Sub-Saharan Africa. Colour is an arbitrary quality, like gender in European languages - "der Tisch" in German is no more a truly masculine table than "la table" in French is physically "feminine." As with this type of sex-based gender, there is a little bit of a sense of "natural colour" in the sense that blue objects might be more likely to be declared blue. People do perceive a certain semantic descriptive quality to the colours, but a blue object could also just as easily be grammatically red.

Where it differs is that colour isn't a classification for nouns in Gluonic at all. It is an intrinsic quality, with grammatical consequences very much like gender in many languages, but it is arbitrarily assigned at will by the speaker and can be reassigned during a discourse by any participant.

Colour is a quality that nouns, pronouns, adjectives, and some other special function words possess. All words of these types have a black radical form that serves as their dictionary entry and the base for derivations, but cannot function in a sentence without being coloured. Agreement, such as between adjectives and their nouns, or pronouns and their referents, is based on colour.

Verbs are themselves black, as are many function words, but verbs use colour agreement marking to mark roles, which is the primary mechanism Gluonic uses to assign roles to nouns, in addition to word order and instead of noun case.

The Mechanism of Colour

All nouns, adjectives and pronouns have complete inflectional paradigms in each colour. When first mentioned in a discourse, they need to be used with a weak colour clitic, a small word that attaches itself to the end of a phrase to signal that the referent is being mentioned for the first time and its colour is being assigned. There is one weak colour clitic for each colour.

There are also three strong colour clitics. These have two functions simultaneously - they assert that their referent has already been mentioned in the discourse, and when applied to a pronoun or noun phrase of the same colour, they serve mainly to emphasise that kind of call back. But when a strong clitic is used with a phrase of a different colour, it serves to change the colour of the referent going forward in the conversation, if the already-assigned colours are creating confusion.

This terminology is translated directly from Gluonic and in the native context is supposed to be evocative of the strong and weak nuclear forces, although the analogy is flawed because they both have to do with colour.

In Classical Gluonic, these mechanisms tie into the kind of pragmatics that are signaled with definiteness or topic marking in other languages, although they are not the sole mechanism for this purpose.

Verbs, on the other hand, do not have colour as an intrinsic quality, but their inflectional paradigms include colour agreement for every possible combination of colours of their subjects and objects, mediated mainly through suffixes.

Colour in Classical Gluonic is tied to vowel frontness and backness - see in Phonology under Vowels. Front vowels /i/ and /e/ are considered Red, mid vowels /a/ and /ə/ are considered Green, and back vowels /o/ and /u/ are considered Blue. All suffixes for colour indication and agreement that have a vowel, all pronouns, and all colour clitics must have a vowel that is appropriate to their colour.

Furthermore, for nouns and adjectives, the colour of the ending is considered to "shine" through the word, resulting in the vowel of the primary (and secondary if present) stressed syllables changing to match it in colour if the black form doesn't already match. Verbs, which agree with their core arguments in colour but don't themselves have colour, are "opaque," and the stem remains black.

In the native writing, this is literally reflected by writing nouns, pronouns and adjectives in the colour font that matches their grammatical colour, and writing the symbols for the stems of verbs and other kinds of black words in black.

Weak Colour Clitics

Weak colour clitics are grammatically required when newly mentioning a referent other than a first or second person referent in a discourse. They attach as a suffix to the last word in a noun phrase, whatever it may be, and agree with it in colour.

The weak clitic can actually be omitted sometimes for rhetorical effect in a place where it is usually required, particularly in speech and informal writing as opposed to formal writing. Treating a referent like it has been mentioned already even when it hasn't invites the listener to think back to an earlier conversation or some other kind of common knowledge. It is a highly idiomatic rhetorical trick and hard for for people whose first language doesn't use a similar device to do well, so not encouraged for learners. A "weak-strong" clitic is often a better choice for these kinds of callbacks to avoid disorienting the listener.

In the Sanderson romanisation, clitics are shown attached to their host word separated by an apostrophe. The apostrophe does not indicate shortening or have phonological consequences, it's just a visual convenience. The Bourque forms are codes written in lowercase to correspond to the logographic glyph that represents the clitic in native orthography.

Strong Colour Clitics

Strong colour clitics are never grammatically required. They do the opposite of a weak clitic - they assert that the referent noun phrase is one that has already been mentioned, and serve a rhetorical or pragmatic function. If they attach to a phrase with a different colour than their own, they have the additional effect of changing the colour of that referent going forward in the discourse. This is typically employed to get two referents you want to talk about into different colours to make them easier to tell apart when they have previously assigned the same colour.

Weak-Strong Clitic Combinations ("Forgotten Colour")

The clitic types can be applied to a noun phrase at the same time. The weak clitic is applied first, then the strong clitic. The two clitics must be of the same colour, and agree with the colour of the phrase. This device is applied far more in speech or casual written communication than in formal writing. What this combination says is that the speaker has forgotten the proper colour of the referent, is acknowledging both that it is has been mentioned before and that the speaker cannot remember its colour, and assigns it a new colour.