Ubykh, an extinct Northwest Caucasian language, has the largest consonant inventory of all documented languages that do not use clicks, and also has the most disproportional ratio of phonemic consonants to vowels. It has consonants in at least eight, perhaps nine, basic places of articulation and 29 distinct fricatives, 27 sibilants, and 20 uvulars, more than any other documented language. Some Khoisan languages, such as Taa (or !Xóõ), may have larger consonant inventories due to their extensive use of click consonants, although some analyses view a large proportion of the clicks in these languages as clusters, which would bring them closer into line with the Caucasian languages.
Consonants
Standard Ubykh Phonology
Below is an International Phonetic Alphabet representation of the Standard Ubykh consonant inventory.
Note the large number of basic series; Ubykh has basic consonants at nine places of articulation. The glottal stop is also noted, but only as an allophone of . The three postalveolar series have traditionally been called "postalveolar", "alveolo-palatal", and "retroflex", respectively, and have been transcribed with their associated symbols. The laminal and apical postalveolar series are more accurately transcribed as and , respectively. There is no standard IPA notation for the laminal-closed postalveolar series. They are transcribed , , , etc. by Catford. The velar stops and the labiodental fricative are only found in Turkish and Circassian loanwords. Out of the labials, the fricatives are labiodental, the others bilabial. /tʷ, dʷ, tʷʼ/ were in free variation with [t͡p, d͡b, t͡pʼ].
All but four of the 84 consonants are found in native vocabulary. The plain velars and the voiced labiodental fricative are found mainly in loans and onomatopoeia: ('crow') from Turkish karga), ('slat, batten') from Laz k'avari 'roofing shingle'), ('estate, legacy') from Turkish vakıf), ('the sound of glass breaking'). As well, the pharyngealised labial consonants are almost exclusively noted in words where they are associated with another pharyngealised consonant (for instance, 'handful'), but are occasionally found outside this context (for example, the verb root 'to explode, to burst'). Finally, is mainly found in interjections and loans, with ('now') the only real native word to contain the phoneme. The frequency of consonants in Ubykh is quite variable; the phoneme alone accounts for over 12% of all consonants encountered in connected text, due to the presence of the phoneme in the ergative and oblique singular and plural case suffixes, the third person singular and plural ergative verbal agreement prefix, the adverbial derivative suffix, the present and imperfect tense suffixes, and in suffixes denoting several non-finite verb forms.
Very few allophones of consonants are noted, mainly because a small acoustic difference can be phonemic when so many consonants are involved. However, the alveolopalatal labialised fricatives were sometimes realised as alveolar labialised fricatives , and the uvular ejective stop was often pronounced as a glottal stop in the past tense suffix -, due to the influence of the Kabardian and Adyghe languages.
The consonant has not been attested word-initially, and is found initially only in the personal name , but every other consonant can begin a word. Restrictions on word-final consonants have not yet been investigated; however, Ubykh has a slight preference for open syllables (CV) over closed ones (VC or CVC). The pharyngealised consonants and have not been noted word-finally, but this is probably a statistical anomaly due to the rarity of these consonants, each being attested only in a handful of words.
The alveolar trill is not common in native Ubykh vocabulary, appearing mostly in loan words. However, the phoneme carries a phonaesthetic concept of rolling or a repeated action in a few verbs, notably ~ ('to roll around') and ~ ('to slither').
Karacalar Ubykh Phonology
A divergent dialect of Ubykh spoken by Osman Güngör, an inhabitant of Karacalar in Balıkesir province was investigated by Georges Dumézil in the 1960s. Below is an International Phonetic Alphabet representation of the Karacalar Ubykh consonant inventory.
Güngör's speech differed phonologically from Standard Ubykh in a number of ways: