Inhistorical linguistics, asound change is achange in thepronunciation of a language. A sound change can involve the replacement of one speech sound (or, more generally, onephonetic feature value) by a different one (calledphonetic change) or a more general change to the speech sounds that exist (phonological change), such as the merger of two sounds or the creation of a new sound. A sound change can eliminate the affected sound, or a new sound can be added. Sound changes can be environmentally conditioned if the change occurs in only somesound environments, and not others.
The term "sound change" refers todiachronic changes, which occur in a language's sound system. On the other hand, "alternation" refers to changes that happensynchronically (within the language of an individual speaker, depending on the neighbouring sounds) and do not change the language'sunderlying system (for example, the-s in theEnglish plural can be pronounced differently depending on the preceding sound, as inbet[s],bed[z], which is a form of alternation, rather than sound change). Since "sound change" can refer to the historical introduction of an alternation (such as postvocalic /k/ in theTuscan dialect, which was once [k] as indi [k]arlo 'of Carlo' but is now [h]di [h]arlo and alternates with [k] in other positions:con [k]arlo 'with Carlo'), that label is inherently imprecise and must often be clarified as referring to either phonemic change or restructuring.
Research on sound change is usually conducted under the working assumption that it isregular, which means that it is expected to apply mechanically whenever its structural conditions are met, irrespective of any non-phonological factors like the meaning of the words that are affected. Apparent exceptions to regular change can occur because of dialect borrowing, grammatical analogy, or other causes known and unknown, and some changes are described as "sporadic" and so they affect only one or a few particular words, without any apparent regularity.
TheNeogrammarian linguists of the 19th century introduced the termsound law to refer to rules of regular change, perhaps in imitation of the laws of physics,[1] and the term "law" is still used in referring to specific sound rules that are named after their authors likeGrimm's law,Grassmann's law,etc. Real-world sound laws often admit exceptions, but the expectation of their regularity or absence of exceptions is of greatheuristic value[further explanation needed] by allowing historical linguists to define the notion ofregular correspondence by thecomparative method.[citation needed]
Each sound change is limited in space and time and so it functions in a limited area (within certaindialects) and for a limited period of time. For those and other reasons, the term "sound law" has been criticized for implying a universality that is unrealistic for sound change.[2]
A sound change that affects the phonological system or the number or the distribution of itsphonemes is aphonological change.
The following statements are used as heuristics in formulating sound changes as understood within theNeogrammarian model. However, for modern linguistics, they are not taken as inviolable rules but 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 an original X.
Sound change ignores grammar: A sound change can have only phonological constraints, like X > Z inunstressedsyllables. For example, it cannot affect onlyadjectives. The only exception is that a sound change may recognise word boundaries, even when they are unindicated byprosodic clues. Also, sound changes may beregularized ininflectional paradigms (such as verbal inflection), when it is no longerphonological butmorphological in nature.[3]
Sound change is exceptionless: If a sound change can happen at a place, it will affect all sounds that meet the criteria for change. Apparent exceptions are possible because ofanalogy and other regularization processes, another sound change, or an unrecognized conditioning factor. That is the traditional view expressed by the Neogrammarians. In the past decades, however, it has been shown[by whom?] that sound change does not necessarily affect all possible words.[citation needed] However, when a sound change is initiated, it often eventually expands to the wholelexicon. For example, theSpanish fronting of theVulgar Latin [g] (voiced velar stop) before [i e ɛ] seems to have reached every possible word. By contrast, the voicing of word-initial Latin [k] to [g] occurred incolaphus >golpe andcattus >gato but not incanna >caña. See alsolexical diffusion.
Sound change is inevitable: All languages vary from place to place and time to time, and neither writing nor media prevents that change.
is to be read as "Sound A changes into (or is replaced by, is reflected as, etc.) sound B". Therefore, A belongs to an older stage of the language in question, and B belongs to a more recent stage. The symbol ">" can be reversed, B < A, which also means that the (more recent) B derives from the (older) A":
The two sides of such a statement indicate only the start and the end of the change, but additional intermediate stages may have occurred. The example above is actually a compressed account of asequence of changes: *[t] first changed to[θ] (like the initial consonant ofEnglishthin), which has since yielded[f] and can be represented more fully:
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 to B when it is 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 (in which the V stands for any vowel)
= "Intervocalic [b] (inherited fromLatin) became [v] inItalian" (such as incaballum, dēbet >cavallo 'horse',deve 'owe (3rd pers. sing.)'
Here is a second example:
PIr. [−cont][−voi] > [+cont] /__[C][+cont]
= "A preconsonantal voiceless non-continuant (voiceless stop) changed into corresponding a voiceless continuant (fricative) inProto-Iranian (PIr.)" when it was immediately followed by a continuant consonant (aresonant or a fricative):Proto-Indo-Iranian *pra 'forth' >Avestanfra; *trayas "three" (masc. nom. pl.)> Av.θrayō; *čatwāras "four" (masc. nom. pl.) > Av.čaθwārō; *pśaws "of a cow" (nom. *paśu) > Av.fšāoš (nom.pasu). The fricativization did not occur before stops and so *sapta "seven" > Av.hapta. (However, in the variety ofIranian that led toOld Persian, fricativization occurred in all clusters: Old Persianhafta "seven".)
The symbol "#" stands for a word boundary (initial or final) and so the notation "/__#" means "word-finally", and "/#__" means "word-initially":
Inhistorical linguistics, a number of traditional terms designate 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; seephonological change.
Assimilation: One sound becomes more like another, or (much more rarely) two sounds become more like each other. Example: in Latin the prefix *kom- becomescon- before anapical stop ([td]) or[n]:contactus "touched",condere "to found, establish",connūbium "legal marriage". The great majority of assimilations take place between contiguous segments,[citation needed] and the great majority involve the earlier sound becoming more like the later one (e.g. inconnūbium,m- + n becomes-nn- rather than-mm-). Assimilation between contiguous segments are (diachronically speaking) exceptionless sound laws rather than sporadic, isolated changes.[citation needed]
Dissimilation: The opposite of assimilation. One sound becomes less like another, or (much more rarely) two sounds become less like each other. Examples: Classical Latinquīnque/kʷiːnkʷe/ "five" > Vulgar Latin *kinkʷe (whence Frenchcinq, Italiancinque, etc.);Old Spanishomne "man" > Spanishhombre. The great majority of dissimilations involve segments that arenot contiguous, but, as with assimilations, the great majority involve an earlier sound changing with reference to a later one. Dissimilation is usually a sporadic phenomenon, butGrassmann's Law (in Sanskrit and Greek) exemplifies a systematic dissimilation. If the change of a sequence of fricatives such that one becomes a stop is dissimilation, then such changes asProto-Germanic *hs to/ks/ (spelledx) in English would count as a regular sound law: PGmc. *sehs "six" >Old Englishsiex, etc.
Metathesis: Two sounds switch places. Example: Old Englishthridda became Middle Englishthird. Most such changes are sporadic, but occasionally a sound law is involved, as Romance *tl > Spanishld, thus *kapitlu, *titlu "chapter (of a cathedral)", "tittle" > Spanishcabildo, tilde. Metathesis can take place between non-contiguous segments, as Greekamélgō "I milk" > Modern Greekarmégō.
Lenition: "Weakening" of a consonant from one that takes more effort to pronounce (and more constriction in the vocal tract) to one that takes less, e.g. astop consonant becoming anaffricate orfricative.
Fortition: the opposite of lenition, "strengthening" a consonant, e.g. anapproximant becoming an affricate or fricative.
Reduction: Whereas the weakening of consonants is calledlenition, the weakening of vowels is calledreduction. For example, in most varieties of English, unstressed vowels often reduce to aschwa, such as the two a's inarena.
Sandhi: Conditioned changes that take place at word-boundaries but not elsewhere. It can bemorpheme-specific, as in the loss of the vowel in the enclitic forms of Englishis/ɪz/, with subsequent change of/z/ to/s/ adjacent to a voiceless consonantFrank's not here/ˈfræŋksnɒtˈhɪər/. Or a small class of elements, such as the assimilation of the/ð/ of Englishthe, this andthat to a preceding/n/ (including the/n/ ofand when the/d/ is elided) or/l/:all the often/ɔːllə/,in the often/ɪnnə/, and so on. As in these examples, such features are rarely indicated in standard orthography. In a striking exception, Sanskrit orthography reflects a wide variety of such features; thus,tat "that" is writtentat, tac, taj, tad,ortan depending on what the first sound of the next word is. These are all assimilations, but medial sequences do not assimilate the same way.
Haplology: The loss of a syllable when an adjacent syllable is similar or (rarely) identical. Example: Old EnglishEnglaland became Modern EnglishEngland, or the common pronunciation ofprobably as[ˈprɒbli]. This change usually affects commonly used words. The wordhaplology itself is sometimes jokingly pronouncedhaplogy.
Elision,aphaeresis,syncope, andapocope: All are losses of sounds. Elision is the loss of unstressed sounds, aphaeresis the loss of initial sounds, syncope is the loss of medial sounds, and apocope is the loss of final sounds.
Elision examples: in the southeastern United States, unstressed schwas tend to drop, so "American" is not/əˈmɛɹəkən/ but/ˈmɚkən/. Standard English ispossum <opossum.
Syncope examples: the Old French word for "state" isestat, but thes disappeared, yieldingétat. Similarly, the loss of/t/ in Englishsoften, hasten, castle, etc.
Apocope examples: the final -e[ə] in Middle English words was pronounced, but is only retained in spelling as asilent E. In English/b/ and/ɡ/ were apocopated in final position after nasals:lamb, long/læm/,/lɒŋ~lɔːŋ/.
Epenthesis (also known as anaptyxis): The introduction of a sound between two adjacent sounds. Examples: Latinhumilis > Englishhumble; in Slavic an -l- intrudes between a labial and a following yod, as *zemya "land" > Russianzemlya (земля). Most commonly, epenthesis is in the nature of a "transitional" consonant, but vowels may be epenthetic: non-standard Englishfilm in two syllables,athlete in three. Epenthesis can be regular, as when the Indo-European "tool" suffix *-tlom everywhere becomes Latin -culum (sospeculum "mirror" < *speḱtlom,pōculum "drinking cup" < *poH3-tlom). Some scholars reserve the termepenthesis for "intrusive" vowels and useexcrescence for intrusive consonants.
Prothesis: The addition of a sound at the beginning of a word. Example: word-initial/s/ + stop clusters in Latin gained a preceding/e/ in Old Spanish and Old French; hence, the Spanish word for "state" isestado, deriving from Latinstatus.
Nasalization: Vowels followed by nasal consonants can become nasalized. If the nasal consonant is lost but the vowel retains its nasalized pronunciation, nasalization becomesphonemic, that is, distinctive. Example: French "-in" words used to be pronounced[in], but are now pronounced[ɛ̃], and the[n] is no longer pronounced (except in cases ofliaison).
Examples of specific sound changes in various languages
