Consonant Harmony: Assimilation, Typology & Language Evolution in Conlanging

Vowel harmony (synharmonism) is the fundamental phonetic law forming the backbone of almost all Turkic languages. It requires all vowels in a word to belong to the same 'team' - either all hard/back vowels (a, o, u, ы) or all soft/front vowels (e, ö, ü, i). In classical Chagatai, this law was absolutely inviolable. However, Uyghur completely preserved this ancient feature, while standard literary Uzbek lost it entirely. This loss resulted from Uzbek's development in Transoxiana cities (Bukhara, Samarkand, Tashkent) in close contact with Tajik (Persian), which never had vowel harmony. Under Iranian influence, Uzbek phonetics was significantly altered, causing suffixes to become 'frozen' in hard forms regardless of the root. This represents a fundamental systemic shift, not merely a superficial change.

The video explains the phenomenon of vowel harmony in Turkic languages. The video notes that in Turkic languages, vowels in a word tend to be either all front or all back, creating a harmonic system. The video explains that this is a distinctive feature of Turkic languages and is not found in Indo-European languages. The video notes that this vowel harmony system affects not just vowels but also consonants, creating a complex phonological system that is characteristic of the Turkic language family.

Vowel harmony (singarmanizm) is a defining characteristic of Turkic languages where vowels within a word must harmonize—thick (back) vowels must harmonize with each other, and thin (front) vowels must harmonize with each other, creating a rhythmic and aesthetic quality that distinguishes Turkic languages from other language families.

Turkish vowel harmony is based on vowel quality: thick vowels (a, ı, o, u) must be followed by thick vowels, while thin vowels (e, i, ö, ü) must be followed by thin vowels. Large vowel harmony determines if a word is Turkish or foreign. Small vowel harmony has two rules: a,e,ı,i must be followed by a,e,ı,i; o,ö,u,ü must be followed by a,e,ı,i,u,ü. Harmony is not checked for single-syllable words, foreign words, or compound words. Turkish is a living language, so some words have changed. Suffixes are generally multiform and maintain harmony, but monomorphemic suffixes like '-yor', '-ken', '-ki', '-daş', '-gil', '-leyin', '-ım', '-trak' break harmony.

Vowel harmony (ünlü uyumu) occurs when vowels in a word change to match the preceding vowel. For example, in 'aklımız', the 'ı' changes to 'i' because it follows 'l' which is a soft consonant. Consonant harmony (ünsüz uyumu) occurs when consonants change based on preceding sounds. For example, in 'yurdumuz', the 'd' changes to 'z' because it follows 'r' which is a soft consonant. These harmony rules ensure smooth pronunciation in Turkish.

To evolve a vowel harmony system, take your basic set and make it the vowel inventory of your proto-language. Then implement sound changes that specifically front or back your proto-vowels to establish the desired harmony. Umlaut is particularly useful - it's a sound change where high vowels cause vowels in previous syllables to front or back. The more harmony-friendly changes you implement, the more justified your language's vowel harmony becomes. This approach connects historical sound changes to modern harmony patterns.

Phonology is a branch of linguistics concerned with the systematic organization of sounds in languages, focusing on the study of phoneme systems in particular languages. It has four main branches: Segmental Phonology (analyzes speech into discrete segments like phonemes and phonological rules), Suprasegmental Phonology (analyzes features extending over multiple segments such as intonation and stress), Diachronic Phonology (studies sound system patterns through the history of language), and Synchronic Phonology (studies sound patterns regardless of historical change).

Vowel harmony operates through four mechanisms: front/back, height, rounding, and ATR harmony. The creator chose front and rounding harmony for their constructed language. ATR harmony in Mongolian evolved from a front/back distinction where e and E vowels lost fronting and became tense variants. Similarly, Manchu's vowel system shows front vowel shifts. Rounding harmony typically co-occurs with other harmony types and varies across languages—Turkish applies it only to high vowels, while Mongolian and Manchu apply it only to low vowels with blocking rules. Vowel classifications are relative and don't always match actual phonetic positions. Sound changes can destroy harmony systems by altering vowel positions or eliminating distinctions. The pristine system serves as a foundation before introducing irregularities through sound changes that shift vowels within the vowel quadrangle, making the system feel more natural and authentic.

This comprehensive section covers vowel harmony across linguistic scales. It begins with assimilation fundamentals—sounds changing to become similar to adjacent sounds for articulatory efficiency, illustrated through German CH and English C. It progresses to vowel harmony extending beyond adjacency to entire words, using Kazan Tatar's five-front-five-back system as the primary example. The section then explores advanced systems like Turkish's two-dimensional harmony based on backness and roundedness, and Wolof's asymmetric harmony based on advanced tongue root (ATR) position. Key functional purposes emerge: reducing articulatory effort and serving as segment boundary markers. The section concludes by examining how harmony systems can disappear, leaving legacies in language change—particularly English i-mutation (umlaut) that shaped the Great Vowel Shift and modern paradigms like 'mouse/mice.' This demonstrates how vowel harmony operates through abstract categorical distinctions and shapes language evolution over centuries.

Historical phonology studies how speech sounds change over long periods. The word 'light' exemplifies this: from Proto-Indo-European *leot (6,000 years ago) through Germanic *le (3,000 years ago), Old English 'le' (1,500 years ago), Middle English 'le' (1,000 years ago), to Modern English 'light' (200-300 years ago). This 6,000-year journey demonstrates systematic sound changes including fricative loss, vowel lengthening, and dissimilation.

Nonconcatenative morphology creates word forms through internal vowel and consonant changes rather than affixation, using mechanisms like umlaut (vowel fronting/raising), consonant gradation (gemination), metathesis (sound swapping), and reduplication to distinguish grammatical categories while obscuring the relationship between related words; when combined with vowel harmony systems, these processes create complex, opaque morphological patterns that make different forms of the same root appear unrelated despite sharing a common origin.

This extended segment demonstrates the iterative process of implementing phonological rules in conlang design. The hosts discuss implementing spirantization (S and Z becoming SHA and JA) through community voting, using multiple poll sources to reach consensus. They spend considerable time troubleshooting rule ordering issues, discovering that placing rules in the wrong position causes unintended interactions with subsequent rules. The solution involves repositioning rules after other rules that might interfere. They also discuss consonant classification, noting that affricates are treated as single units rather than separate stop and fricative components, which affects how rules apply. They discuss obstruent devoicing before voiceless consonants and how this applies to all obstruents except nasals, approximants, and trills. This demonstrates the importance of precise phonological definitions and the iterative nature of conlang development.

This comprehensive segment addresses advanced phonological processes essential for realistic language development. Key topics include: implementing apposition rules where consonant clusters are broken by inserting epenthetic vowels (using null insertion with asterisks); defining prohibited clusters and ensuring repair strategies prevent illegal formations; understanding the distinction between class notation (liquids) and feature notation in rule environments; and applying exception handling with double forward slashes to override general rules. The segment emphasizes that successful implementation requires redefining syllable structure to accommodate new cluster types and carefully ordering rules so that general rules precede specific exceptions.

Two fundamental segment manipulation processes reshape phonological structure. Epenthesis inserts segments to resolve articulatory difficulties: English adds /e/ before sibilant clusters in plurals (e.g., 'matches' → /mætʃɪz/, 'houses' → /haʊzɪz/). Elision deletes segments: French deletes word-final consonants before consonant-initial words (e.g., 'cafe' + 'americain' → 'caféaméricain'). Transformational notation provides visual clarity by numerating segments and showing positional changes: metathesis reverses adjacent sounds to break clusters (V1C2C3C4 → C2V1C3C4), while coalescence merges adjacent sounds into single entities sharing combined features (Korean: C[-cont] + G → C[-cont][+asp]).

This segment explores advanced phonological processes including glide rounding harmony, where semivowel rounding takes on adjacent vowel characteristics, and bidirectional vowel quality spread affecting both preceding and following elements. The discussion analyzes historical form development and demonstrates how these processes naturally emerge from phonetic tendencies. Parallel analysis examines morpheme segmentation techniques, distinguishing stems from endings to enable learner acquisition. Multiple declension classes are identified (a-stems, b-stems, c-stems, schwa-stems, u-stems), each following distinct morphological patterns. This demonstrates how systematic phonological organization enables predictable language learning and acquisition.