Sound change

Sound change or phonetic change is a historical process of language change consisting in the replacement of one speech sound or, more generally, one phonetic feature by another in a given phonological environment. Sound change is supposed to be regular, which means that it should be expected to apply mechanically whenever its structural condition is met, irrespective of any non-phonological factors (such as the meaning of the words affected). Hence the somewhat hyperbolic term sound law, introduced in the 19th c. and still applied traditionally to some of the historically important sound changes, e.g. Grimm's law. While real-world sound changes often admit of exceptions (for a variety of known reasons, and sometimes without a known reason), the expectation of their regularity or "exceptionlessness" is of great heuristic value, since it allows historical linguists to define the notion of regular correspondence (see: comparative method).

Each sound change is limited in space and time. It means it functions within a specified area (only in some dialects / ethnolects) and within a specified period of time. These limitations are one of the reasons for which some scholars refuse using the term "sound law" (asserting that laws should not have such spatial and temporal limitations) and replace it with phonetic rule.

Sound change is part of the larger process of language change.

The formal notation of sound change

A > B

is to be read, "A changes into (or is replaced by, is reflected as, etc.) B". It goes without saying that A belongs to an older stage of the language in question, whereas B belongs to a more recent stage. The symbol ">" can be reversed:

B < A

"(more recent) B derives from (older) A"

For example,

POc. *t > Rot. f

= "Proto-Oceanic *t is reflected as ^* in the Rotuman language."

The two sides of such an equation indicate start and end points only, and do not imply that there are not additional intermediate stages. The example above is actually a compressed account of a sequence of changes: *t changed first into a dental fricative (like the initial consonant of English thin), which has yielded present-day ^*. This can be represented more fully as:

t > > f

Unless a change operates unconditionally (in all envirnoments), we have to specify the context in which it applies:

A > B /X__Y

= "A changes into B when preceded by X and followed by Y." For example:

It. b > v /^*__^*, which can be simplified to just

It. b > v /V__V

where the capital V stands for any given vowel.

= "Intervocalic (inherited from Latin) became [v in Italian" (e.g. in caballum, dēbet > cavallo 'horse', deve 'owe (3sg.)'

PIr. > ^*C

= "Preconsonantal voiceless non-continuants (i.e. voiceless stops) changed into corresponding voiceless continuants (fricatives) in Proto-Iranian", so that e.g. Proto-Indo-European *pr, *pt > Proto-Iranian *fr, *ft (features not mentioned explicitly in the formulation of the change, such as the place of articulation, are assumed not to change).

If the symbol "#" stands for a word boundary (initial or final), the notation "/__#" = "word-finally", and "/#__" = "word-initially". For example:

Gk. ^* > Ø /__#

= "Word-final stops were deleted in Greek." Which can be simplified to

Gk. P > Ø / __#

where capital P stands for any plosive.

Rules of sound change

The following statements are used as heuristics in formulating sound changes as understood within the Neogrammarian model. However, for modern linguistics, they are not taken as inviolable rules; rather, they are seen as guidelines.

Sound change has no memory: Sound change does not discriminate between the sources of a sound. If a previous sound change causes X,Y > Y (features X and Y merge as Y), a new one cannot affect only original X's. If it helps, think of a stampede of animals, each erasing its predecessor's footprints.

Sound change ignores grammar: A sound change can only have phonological constraints, like X > Z in unstressed syllables. It cannot drop final W, except on adjectives, or the like. The only exception to this is that a sound change may or may not recognise word boundaries, even when they are not indicated by prosodic clues. Also, sound changes may be regularized in inflectional paradigms (such as verbal inflection), in which case the change is no longer phonological but morphological in nature.

Sound change is exceptionless: If a sound can happen at a place, it will. It affects all sounds that meet the criteria for change. Apparent exceptions are possible, due to analogy and other regularization processes, or another sound change, or an unrecognized conditioning factor. This is the traditional view, expressed by the Neogrammarians. In past decades it has been shown that sound change doesn't necessarily affect all the words it in principle could. However, when a sound change is initiated, it usually expands to the whole lexicon, given enough time. See also lexical diffusion.

Sound change is unstoppable: Nobody knows why, but all languages vary from place to place and time to time, and the use of writing does not prevent this change.

Types of sound change

Sound change is informally divided into influenced and spontaneous. Influenced sound changes are sound changes affected by adjacent sounds. Spontaneous sound changes are the opposite. There is some overlap between the two types.

Spontaneous sound change

The "Sound Laws" of Grimm and Verner and others are spontaneous sound changes. Another spontaneous sound change transformed Old English into Middle English . The collapse of many of Middle English's consonant clusters is also a spontaneous sound change. For example, Middle English ^* in Modern English.

Conditioned sound change

There are several types of conditioned sound change, that is, sound changes that occur due to specific conditioning factors.

Assimilation: One sound becomes more like another, or two sounds become more like each other. Example: the and ^*.

Dissimilation: The opposite of assimilation. One sound becomes less like another, or two sounds become less like each other. Example: The first half of the first vowel in Middle English bite has gradually grown less and less like the second half: > > > in modern English bite.

Metathesis: Two sounds switch places. Example: Old English thridda has become Modern English third.

Tonogenesis: Syllables come to have distinctive pitch countours. Final consonants lenite, with stops becoming and fricatives becoming . These sounds affect the pitch contour of the previous syllable, and at some point, speakers take the countours (i.e., tones) as primary, rather than the consonants, which are subsequently lost.

Liaison: The introduction of a sound between words. Examples: French "il y a" becomes "y a t-il" when inverted. The postvocalic in some English dialects is pronounced only if the following word starts with a vowel.

Elision, Apocope, and Syncope: All losses of sounds. Elision is the loss of unstressed sounds, apocope is the loss of final sounds, and syncope is the loss of medial sounds. Elision example: in the southeastern United States, unstressed schwas tend to drop, so "American" is not but . Apocope example: the Old French word for "state" is "estat," but the "s" has dropped since then, yielding, "état." Syncope example: the final in Middle English words was pronounced, but was lost, and is only retained in spelling as "silent e."

Epenthesis: The introduction of a sound between others. Example: in some dialects of English, a is introduced between and , like in prince .

Prothesis: The addition of a sound. It differs from liaison in that prothesis always affects a single word, whereas liaison depends on other words. Example: /s/ + stop clusters in Latin gained a preceding /e/ in Old Spanish and Old French; hence, the Spanish word for "state" is "estado," deriving from Latin "status."

Haplology: The loss of a syllable because an adjacent syllables is similar or identical. Example: Old English "Anglaland" became Modern English "England", or the common pronunciation of particularly as particuly. This change usually affects commonly used words. The word haplology itself might reduce to *haplogy if it were common enough to be affected by this change.

Nasalization: Vowels followed by nasal consonants are usually nasalized. If the nasal consonant is lost but the vowel retains its nasalized pronunciation, nasalization has become phonemic, that is, distinctive. Example: French "-in" words used to be pronounced but are now pronounced as , and the [n is no longer pronounced.

Examples of specific historical sound changes

Historical linguistics | Phonology | Sound laws