Geoff's Collection of Sound Changes

Geoff's homepage -> Artificial Languages -> Sound changes

Last update: 17 March 2004

This page presents a survey of the more common types of sound-change for the benefit of fledgeling conlangers who want to create new dialects or descendants from their creations. Obviously, not every type of sound-change can be included here; however, I am more than happy to accept submissions. Nor is it practical to provide examples of each sound-change beyond referring to some languages in which it takes place. More so than my other pages, this page desperately needs input from others, especially with non-Indo-European types of sound-change.

Notes about sound-changes

The Sonority Hierarchy

The Sonority Hierarchy is a useful concept which lies behind some theories about sound-change. It orders sounds according to how vowel-like or consonant-like they are; as usually presented, it looks something like this:

  1. Voiceless stops and affricates (e.g. /p t ts tS k/)
  2. Voiced stops and affricates (/b d dz dZ g/)
  3. Voiceless fricatives (/f T s S x/)
  4. Voiced fricatives (/v D z Z G/)
  5. Approximants and liquids (/l r w j/)
  6. High vowels (/i y 1 } u M/)
  7. Mid vowels (/e 2 o 7/ and /E 9 O V/)
  8. Low vowels (/a & A Q/)

Conditioning

It is rare, and from a conlanger's point of view not very interesting, for a sound-change to occur everywhere, i.e. in all environments without distinction; one such example is the change of Vulgar Latin /u/ to /y/ in Gallo-Romance. It is more usual for a sound-change to occur in some environments and not others, i.e. for it to be environmentally conditioned. For example, /u/ also became /y/ in older varieties of Germanic, but only before (depending on the language) /i/ or /j/; thus Old English /mu:s/ "mouse", plural /mu:si/ > /my:si/ (later > /my:s/).

Mergers and splits

Merger is the process by which two or more phonemes come to have identical allophones (different phonetic realisations) in all environments and become for all practical purposes the same phoneme. Example mergers are:

Split is the reverse process by which one phoneme, which has two (or more) allophones in different environments, becomes two phonemes as a result of the loss of the conditioning environments. The split of /u:/ into /u:/ and /y:/ above is one example; another example comes from Sanskrit, in which Indo-European /k/ became /tS/ before /e/, and /e/ later merged with /a/; /ke/ and /ka/ thus became /tSa ka/.

Finally there is partial merger, in which one phoneme splits into two, one of which merges with an existing phoneme. For example, a language with /u/ and /o/ may lower some /u/ to /o/ in some environments (e.g. before /a/).

In general, splits increase the number of phonemes, partial mergers have no change but affect the distribution, and mergers reduce it.

Parallel changes

If one phoneme undergoes a particular change, related phonemes will probably also undergo the same change; the motivation for this is generally believed to be the desire to prevent or minimise imbalances in a sound-system. The lenition of intervocalic voiced stops /b d g/ to voiced fricatives /B D G/ in Western Romance is such an example; it is unlikely that just one stop would have changed. An exception may be seen in Dutch, in which older /B D/ have become /b d/ in some environments, but older /G/ has not become /g/.

Series changes (chain-shifts)

Chain-shifts are sets of sound-changes in which one change causes another to prevent a merger, which in turn causes a third, and so on (a push-chain). Alternatively, one change creates an imbalance in the sound-system, a second change subsequently takes place to rectify the imblance, but creates another imblance somewhere else, and so on; this is a pull-chain.

An example is the Great Vowel Shift in Middle English, by which /i: e: E: a:/ became /ai i: e: E:/. If this set of changes was caused by the diphthongisation of /i:/ to /ai/, causing /e:/ to raise to fill the resulting gap and so on, it would be a pull-chain. On the other hand, if /a:/ raised to /E:/, pushing the other long front vowels higher, it would be a push-chain. It actually isn't terribly important which explanation is correct in this case.

Motivations

There are many different theories about the general causes of sound change; a particularly debatable one is the desire to avoid morphological ambiguity. Ultimately it may come down to mere entropy. Often, however, the motivations for specific sets of sound-change are uncontroversial; two examples will be described here.

The tendency to rising sonority was responsible for some major restructuring in Proto-Slavonic. This tendency resulted in the phonemes withon a syllable to be ordered from the highest (most consonant-like) in the sonority hierarchy to the lowest; some consequences of this were the loss of all syllable-final stops, the nasalisation of vowels which were followed by /m n/ in the same syllable, the reduction of diphthongs to simple vowels, and the complicated changes of syllables ending in a vowel plus /l r/.

Syllable weight often governs sound changes; the effects depend on the language:

Sound-changes affecting consonants

Lenition and Loss

Lenition is often described as a weakening of the pronunciation of a consonant, moving it down the sonority hierarchy. It typically occurs between vowels or between a vowel and a liquid. Typical changes caused by lenition are:

Lenition is best observed in Romance and especially Celtic.

Lenition may also cause a consonant to vocalise, i.e. become a semivowel:

At its extreme, lenition may result in loss, the complete disappearance of a phoneme. Examples of phonemes which have undergone loss are:

Fortition

Fortition is the reverse of lenition, and is rather less common. Some examples are:

Palatalisation

A very commom type of sound-change, palatalisation occurs when a consonant is found next to a front vowel (commonly /i e/, but sometimes also /y 2/, and in French /a/) or the palatal glide /j/, and consists in the point of articulation of the consonant moving closer to the soft palate (where /j/ is articulated).

Epenthesis

Epenthesis is the insertion of a consonant into a cluster; the new consonant is very commonly pronounced at the same point of articulation as one of its neighbours.

Assimilation

Assimilation consists in one or more consonants becoming more similar to a neighbouring consonant. It can take many forms

Dissimilation

By this change, the opposite of assimilation, one consonant becomes less like a nearby consonant. Interesting examples are found in Romance, where one of two identical liquids in a word changes: Latin arbor > Spanish arból, and ironically Latin similalis > similaris.

Separation

This is the change of a consonant with a complex articulation into two or more consonants with simpler articulations. Many of the examples are theoretical, although the first two are observable in Romance.

Affrication

In High German, /p t k/ > /pf ts kx/ word-initially.

Changes in place of articulation

Some of these are probably varieties of assimilation or dissimilation.

Metathesis

This much less regular change consists of two (sometimes more) phonemes changing places.

Sound-changes affecting vowels

Changes in length are commonly related to stress and syllable structure. A common environment for vowel lengthening is in stressed syllables which do not end in a consonant, as in Italian; similarly, a long vowel may shorten when unstressed (as happened in Latin in final syllables) or when in a closed syllable (also in Latin). Note also how the stressed vowels of English loanwords like divine, serene, profane, pronounce shorten when suffixes are added: divinity, serenity, profanity, pronunciation.

Short vowels may also become long by compensatory lengthening. This sometimes accompanied the loss of a consonant: for example, the /z/ was lost from older Latin nizdos, giving /nidus/; to preserve the weight of the initial syllable, the /i/ was lengthened. Or it can occur when the vowel of a neighbouring syllable is lost, as in some Algonquian languages.

Breaking and diphthongisation

These two terms both refer to the same thing: a vowel, usually long, becomes a diphthong.

Assimilation and monophthongisation

Conversely, the component vowels of a diphthong may become more similar to each other, often becoming a simple vowel with an intermediate quality:

Partial assimilation, which is often a stage on the path towards full assimilation, may be seen in:

These last two changes are assimilations in vowel height.

Stress shifting

By this change, the stress moves from the first element in a diphthong to the second:

Epenthesis

Epenthetic vowels may be exemplified by:

Loss

Unstressed vowels may be lost in a very wide variety of situations; the loss is known as syncope if it is medial and apocope otherwise. For example: Welsh esgidiau > colloquial /sg_0id_ja/, viridis > Spanish verde, Latin panem > Spanish pan, French pain. Final apocope is widespread in French and the history of Germanic.