The linguist John Colarusso has further postulated that some instances of this may also be due to the levelling of an old grammatical class prefix system (so */w-ka/ may have become /kʷa/), on the basis of pairs like Ubykh /ɡʲə/ vs. Kabardian and Abkhaz /ɡʷə/ heart.

The entire family is characterised by a paucity of phonemic vowels (two or three, depending upon the analysis) coupled with rich consonantal systems that include many forms of secondary articulation.

All finite verbs are marked for agreement with three arguments: absolutive, ergative, and indirect object,[7] and there are also a wide range of applicative constructions.

A verb's morphemes indicate the subject's and object's person, place, time, manner of action, negative, and other types of grammatical categories.

All Northwest Caucasian languages are left-branching, so that the verb comes at the end of the sentence and modifiers such as relative clauses precede a noun.

Northwest Caucasian languages do not generally permit more than one finite verb in a sentence, which precludes the existence of subordinate clauses in the Indo-European sense.

Equivalent functions are performed by extensive arrays of nominal and participial non-finite verb forms, though Abkhaz appears to be developing limited subordinate clauses, perhaps under the influence of Russian.

Four main dialects are recognised: Temirgoy, Abadzekh, Shapsugh and Bzhedugh, as well as many minor ones such as Hakuchi spoken by the last speakers of Ubykh in Turkey.

Kabardian has the fewest consonants of any North-Western Caucasian language, with 48, including some rather unusual ejective fricatives and a small number of vowels.

With eighty-one consonants, Ubykh had perhaps the largest inventory in the world aside from the Kx'a and Tuu families of southern Africa with their extensive system of clicks.

Hattic was spoken in Anatolia (Turkey), in the area around ancient Hattusa (modern Boğazköy), until about 1800 BCE, when it was replaced by the Indo-European Hittite language.

It has been conjectured[10][11] that the North-West Caucasian languages may be genetically related to the Indo-European family, at a time depth of perhaps 12,000 years before the present.