Principles of organization of vowel harmony systems in Southern Siberian Turkic languages as indicators of language complexity

We consider the synharmonic systems of modern Southern Siberian Turkic languages according to parameters of language complexity. Instrumental studies of Siberian languages and languages of neighboring areas show that synharmonism is a law defining the phonetic (i. e. phonic and phonological) image of the entire word form, comprising both its vowel and consonant axes. It manifests itself in the rules of consonant and vowel combinability within the monothematic lexeme. Comparative analysis of synharmonic systems in Southern Siberian Turkic languages shows that the most complex synharmonic system (SS) is found in the Tuvan language; the Khakas language is characterized by the lowest phonological complexity of SS; the rest of the languages are located between Tuvan and Khakas on the scale of objective synharmonic complexity. Among the Southern Siberian Turkic languages, the Tuvan synharmonic system is structured with the largest number of correlative attributes: palatal, labial, and pharyngeal. Among the languages we analyze in our paper, only the literary Khakas language uses the contracted type of SS, the palatal attribute alone remaining synharmonically relevant to the system. Synharmonic systems of other languages and dialects can be described as transitional (between full and contracted) with varying degrees of loss of the correlative labial attribute. A rough quantitative analysis of synharmonic systems demonstrates that in the area of Southern Siberian Turkic languages' distribution, processes conducting to the simplification of SS are most evident, both through the unification of algorithms of realization of palatal synharmonism and through the reduction of the sphere of labial vowel harmony (LVH) up to its total obliteration as in the case of the Khakas literary language. Compared to genetically and historically similar languages of Southern Siberia, the Kyrgyz SS, which we used as a reference, is the most complete one, showing minimal trends towards obliteration of LVH. On the other hand, in Southern Siberian Turkic languages we observe various stages of phonetic processes blocking the power of synharmonic laws, which leads to the complication of SS. Malfunctioning of synharmonic algorithms of formation of phonetic word forms and the subsequent growth of the linguistic complexity, may be explained by a number of phonetic factors: the presence of palatal consonants in hard word forms requiring the emergence of soft vowels in postposition; the presence of diphthongs along with monophthongs; various failures in consonant harmony realization rules. The hierarchy of Southern Siberian Turkic synharmonic systems based on parameters of syntagmatic complexity is generally congruent with the results obtained earlier by means of analysis of vocal and consonant systems of these languages in terms of their paradigmatic complexity. The trends the study reveals confirm positive correlation between the levels of complexity of phonological and morphonological systems and language stability degree.