3.3 Phonological Change
Phonological change refers to systematic, rule-governed alterations in the sound system of a language over time. Unlike isolated phonetic variations, phonological changes affect the underlying mental representation of sounds (phonemes) and their distribution patterns. These shifts are typically gradual, conditioned by articulatory, perceptual, structural, or social factors, and can result in significant restructuring of a language's inventory.
Mechanisms of Change
Phonological change operates through several well-documented processes. While often gradual, they can be modeled synchronically as alternations and diachronically as shifts.
1. Assimilation & Dissimilation
Assimilation occurs when a sound becomes more like a neighboring sound, usually in terms of place, manner, or voicing. It is driven by articulatory ease.
Vowel harmony in Turkish: /ev/ (house) → /ev-de/ (locative)
Dissimilation is the reverse: two similar sounds in a word become less alike to avoid perceptual redundancy.
Latin /flos/ (flower) → /flōrem/ (acc. sg.) → Italian /fiore/
2. Lenition & Fortition
Lenition (weakening) involves sounds becoming less sonorous or requiring less articulatory effort: stops → fricatives → approximants → deletion. Fortition (strengthening) is rarer but occurs when sounds become more obstruent or marked.
3. Metathesis
The reordering of sounds within a word or phonological phrase. Often motivated by syllable structure constraints or ease of articulation.
Latin /psyllium/ → /byssium/ → Modern "fennel" (via French)
4. Epenthesis & Elision
Epenthesis inserts a sound to break illicit consonant clusters or fulfill syllable structure requirements. Elision deletes sounds, often unstressed vowels or word-final consonants in connected speech.
Internal vs. External Causes
Historical linguists categorize the drivers of phonological change into two broad classes:
| Category | Driving Factors | Typical Outcome |
|---|---|---|
| Internal | Articulatory ease, perceptual clarity, systemic pressure (e.g., inventory gaps), analogical leveling | Regular sound laws, chain shifts, inventory reduction/expansion |
| External | Language contact, borrowing, bilingualism, sociolinguistic prestige/stigma, child language acquisition patterns | Lexical diffusion, substrate/superstrate influence, mixed phonotactics |
Modern sociophonetics and variationist approaches (Labov, Trudgill) emphasize that external/social factors often initiate changes that are then grammaticalized through internal mechanisms.
Case Studies
Grimm's Law & Consonant Shifts
One of the most famous regular sound changes in Indo-European history. It describes the shift of Proto-Indo-European (PIE) stops into Proto-Germanic fricatives or aspirated stops:
This change was exceptionless in native vocabulary, demonstrating the rule-governed nature of phonological evolution. Verner's Law later explained the distribution of voiced fricatives as conditioned by PIE accent placement.
The Great Vowel Shift
A chain shift affecting Middle English long vowels between the 15th and 18th centuries. High vowels diphthongized, mid vowels raised, creating the modern English vowel system:
Unlike consonant shifts, vowel shifts often lack precise articulatory triggers and are theorized to result from systemic pressure to maintain vowel space distinctions.
Methodological Notes
Reconstructing phonological change relies on:
- Comparative Method: Identifying regular correspondences across related languages
- Internal Reconstruction: Analyzing morphophonemic alternations within a single language
- Lexical Diffusion Model: (Hymes & Wang) Changes spread word-by-word before becoming categorical
- Corpus & Archival Analysis: Tracking variation in historical texts, pronunciation guides, and orthographic reforms
References & Further Reading
- Campbell, L. (2013). Historical Linguistics: An Introduction (3rd ed.). Edinburgh University Press.
- Hock, H. H. (1991). Principles of Historical Linguistics (2nd ed.). Mouton de Gruyter.
- Labov, W. (1994). Principles of Linguistic Change: Internal Factors. Blackwell.
- Maidment, J. (2006). An Introduction to Historical Linguistics. Edinburgh University Press.
- Wang, W. S.-Y. (1969). "Competing Change as a Cause of Residue." Language, 45(3), 9-25.