Sound change

Sound change and alternation
Fortition
Dissimilation

Sound change includes any processes of language change that affect pronunciation (phonetic change) or sound system structures (phonological change). Sound change can consist of the replacement of one speech sound (or, more generally, one phonetic feature) by another, the complete loss of the affected sound, or even the introduction of a new sound in a place where there previously was none. Sound changes can be environmentally conditioned, meaning that the change in question only occurs in a defined sound environment, whereas in other environments the same speech sound is not affected by the change. The term "sound change" refers to diachronic changes, or changes in a language's underlying sound system over time; "alternation", on the other hand, refers to surface changes that happen synchronically and do not change the language's underlying system (for example, the -s in the English plural can be pronounced differently depending on what sound it follows; this is a form of alternation, rather than sound change).

Sound change is usually assumed to be regular, which means that it is expected to apply mechanically whenever its structural conditions are met, irrespective of any non-phonological factors (such as the meaning of the words affected). On the other hand, sound changes can sometimes be sporadic, affecting only one particular word or a few words, without any seeming regularity.

For regular sound changes, the somewhat hyperbolic term sound law is sometimes still used. This term was introduced by the Neogrammarian school in the 19th century and is commonly applied to some historically important sound changes, such as Grimm's law. While real-world sound changes often admit exceptions (for a variety of known reasons, and sometimes without one), 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. This means it functions within a specified area (within certain dialects) and during a specified period of time. For these (and other) reasons, some scholars avoid using the term "sound law" — reasoning that a law should not have spatial and temporal limitations — replacing the term with phonetic rule.

Sound change which affects the phonological system, in the number or distribution of its phonemes, is covered more fully at phonological change.

Contents

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 [f] 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 [θ] (like the initial consonant of English thin), which has yielded present-day [f]. This can be represented more fully as:

t > θ > f

Unless a change operates unconditionally (in all environments), the context in which it applies must be specified:

A > B /X__Y
= "A changes into B when preceded by X and followed by Y."

For example:

It. b > v /[vowel]__[vowel], which can be simplified to just
It. b > v /V__V (where the capital V stands for any given vowel)
= "Intervocalic [b] (inherited from Latin) became [v] in Italian" (e.g. in caballum, dēbet > cavallo 'horse', deve 'owe (3sg.)'

A second example:

PIr. [-cont][-voi] > [+cont]/__[C][+cont]
= "Preconsonantal voiceless non-continuants (i.e. voiceless stops) changed into corresponding voiceless continuants (fricatives) in Proto-Iranian" when immediately followed by a continuant consonant (i.e. resonants and fricatives). Examples: Proto-Indo-Iranian *pra 'forth' > Avestan fra, *trayas "three" (masc.nom.pl.)> Av. θrayō, *čatwāras "four" (masc.nom.pl.) > Av. čaθwārō, *pśaws "of a cow" (nom. *paśu) > Av. fšāoš (nom. pasu). Note that the fricativization does not occur before stops, so *sapta "seven" > Av. hapta. (However, in the variety of Iranian underlying Old Persian, fricativization occurs in all clusters, thus Old Persian hafta "seven".)

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

Gk. [stop] > ∅ /__#
= "Word-final stops were deleted in Greek." Which can be simplified to
Gk. P > ∅ / __#
where capital P stands for any plosive.

Principles 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.

Sound change ignores grammar: A sound change can only have phonological constraints, like X > Z in unstressed syllables. It cannot, for example, only affect adjectives. 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 change 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: All languages vary from place to place and time to time, and neither writing nor media prevent this change.

Terms for changes in pronunciation

There are a number of traditional terms in historical linguistics designating types of phonetic change, either by nature or result. A number of such types are often (or usually) sporadic, that is, more or less accidents that happen to a specific form. Others affect a whole phonological system. Sound changes that affect a whole phonological system are also classified according to how they affect the overall shape of the system; see phonological change.

Examples of specific historical sound changes

References