Vowel reduction

Last updated

In phonetics, vowel reduction is any of various changes in the acoustic quality of vowels as a result of changes in stress, sonority, duration, loudness, articulation, or position in the word (e.g. for the Creek language [1] ), and which are perceived as "weakening". It most often makes the vowels shorter as well.


Vowels which have undergone vowel reduction may be called reduced or weak. In contrast, an unreduced vowel may be described as full or strong.


Common reduced vowels
(IPA provides only ə and ɐ)
Central Near-
Near-close (ɨ)ᵿ (ɵ)
Mid ə
Near-open ɐ

There are several ways to distinguish full and reduced vowels in transcription. Some English dictionaries mark full vowels for secondary stress, so that e.g. ˌɪ is a full unstressed vowel while ɪ is a reduced, unstressed schwi. [lower-alpha 1] Or the vowel quality may be portrayed as distinct, with reduced vowels centralized, such as full ʊ vs reduced ᵿ or ɵ. Since the IPA only supplies letters for two reduced vowels, open ɐ and mid ə, transcribers of languages such as RP English and Russian that have more than these two vary in their choice between an imprecise use of IPA letters such as ɨ and ɵ, [lower-alpha 2] or of custom non-IPA (extended IPA) letters such as and ᵿ.

Weakening of vowel articulation

Cardinal vowel chart showing peripheral (white) and central (blue) vowel space, based on the chart in Collins & Mees (2003:227) Peripheral and central vowel space.svg
Cardinal vowel chart showing peripheral (white) and central (blue) vowel space, based on the chart in Collins & Mees (2003 :227)

Phonetic reduction most often involves a mid-centralization of the vowel, that is, a reduction in the amount of movement of the tongue in pronouncing the vowel, as with the characteristic change of many unstressed vowels at the ends of English words to something approaching schwa. A well-researched type of reduction is that of the neutralization of acoustic distinctions in unstressed vowels, which occurs in many languages. The most common reduced vowel is schwa.

Whereas full vowels are distinguished by height, backness, and roundness, according to Bolinger (1986), reduced unstressed vowels are largely unconcerned with height or roundness. English /ə/, for example, may range phonetically from mid [ə] to [ɐ] to open [a]; English /ᵻ/ ranges from close [ï], [ɪ̈], [ë], to open-mid [ɛ̈]. The primary distinction is that /ᵻ/ is further front than /ə/, contrasted in the numerous English words ending in unstressed -ia. That is, the jaw, which to a large extent controls vowel height, tends to be relaxed when pronouncing reduced vowels. Similarly, English /ᵿ/ ranges through [ʊ̈] and [ö̜]; although it may be labialized to varying degrees, the lips are relaxed in comparison to /uː/, /oʊ/, or /ɔː/. The primary distinction in words like folio is again one of backness. However, the backness distinction is not as great as that of full vowels; reduced vowels are also centralized, and are sometimes referred to by that term. They may also be called obscure, as there is no one-to-one correspondence between full and reduced vowels. [3]

Sound duration is a common factor in reduction: In fast speech, vowels are reduced due to physical limitations of the articulatory organs, e.g., the tongue cannot move to a prototypical position fast or completely enough to produce a full-quality vowel (compare with clipping). Different languages have different types of vowel reduction, and this is one of the difficulties in language acquisition; see, e.g., "Non-native pronunciations of English" and "Anglophone pronunciation of foreign languages". Vowel reduction of second language speakers is a separate study.

Stress-related vowel reduction is a principal factor in the development of Indo-European ablaut, as well as other changes reconstructed by historical linguistics.

Vowel reduction is one of the sources of distinction between a spoken language and its written counterpart. Vernacular and formal speech often have different levels of vowel reduction, and so the term "vowel reduction" is also applied to differences in a language variety with respect to, e.g., the language standard.

Some languages, such as Finnish, Hindi, and classical Spanish, are claimed to lack vowel reduction. Such languages are often called syllable-timed languages. [4] At the other end of the spectrum, Mexican Spanish is characterized by the reduction or loss of the unstressed vowels, mainly when they are in contact with the sound /s/. [5] [6] It can be the case that the words pesos, pesas, and peces are pronounced the same: [ˈpesə̥s].

Vowel inventory reduction

In some cases phonetic vowel reduction may contribute to phonemic (phonological) reduction, which means merger of phonemes, induced by indistinguishable pronunciation. This sense of vowel reduction may occur by means other than vowel centralisation, however.

Many Germanic languages, in their early stages, reduced the number of vowels that could occur in unstressed syllables, without (or before) clearly showing centralisation. Proto-Germanic and its early descendant Gothic still allowed more or less the full complement of vowels and diphthongs to appear in unstressed syllables, except notably short /e/, which merged with /i/. In early Old High German and Old Saxon, this had been reduced to five vowels (i, e, a, o, u, some with length distinction), later reduced further to just three short vowels (i/e, a, o/u). In Old Norse, likewise, only three vowels were written in unstressed syllables: a, i and u (their exact phonetic quality is unknown). Old English, meanwhile, distinguished only e, a, and u (again the exact phonetic quality is unknown).

Specific languages


Stress is a prominent feature of the English language, both at the level of the word (lexical stress) and at the level of the phrase or sentence (prosodic stress). Absence of stress on a syllable, or on a word in some cases, is frequently associated in English with vowel reduction – many such syllables are pronounced with a centralized vowel (schwa) or with certain other vowels that are described as being "reduced" (or sometimes with a syllabic consonant as the syllable nucleus rather than a vowel). Various phonological analyses exist for these phenomena.


Old Latin had initial stress, and short vowels in non-initial syllables were frequently reduced. Long vowels were usually not reduced.

Vowels reduced in different ways depending on the phonological environment. For instance, in most cases, they reduced to /i/. Before l pinguis, an /l/ not followed by /i iː l/, they became Old Latin /o/ and Classical Latin /u/. Before /r/ and some consonant clusters, they became /e/.

fáctos, *ád-factos > fáctos, áffectos "made, affected" (participles)

In Classical Latin, stress changed position and so in some cases, reduced vowels became stressed. Stress moved to the penult if it was heavy or to the antepenult otherwise.

fáctus, afféctus

Romance languages

Vulgar Latin had seven vowels in stressed syllables (/a, ɛ, e, i, ɔ, o, u/). In unstressed syllables, ɛ merged into e and ɔ merged into o, yielding five possible vowels. Some Romance languages, like Italian, maintain this system, while others have made adjustments to the number of vowels permitted in stressed syllables, the number of vowels permitted in unstressed syllables, or both. Some Romance languages, like Spanish, French and Romanian, lack vowel reduction altogether.


Standard Italian has seven stressed vowels and five unstressed vowels, as in Vulgar Latin. Some regional varieties of the language, influenced by local vernaculars, do not distinguish open and closed e and o even in stressed syllables.


Neapolitan has seven stressed vowels and only four unstressed vowels, with e and o merging into /ə/. At the end of a word, unstressed a also merges with e and o, reducing the number of vowels permitted in this position to three.


Sicilian has five stressed vowels (/a, ɛ, i, ɔ, u/) and three unstressed vowels, with /ɛ/ merging into /i/ and /ɔ/ merging into /u/. Unlike Neapolitan, Catalan or Portuguese, Sicilian incorporates this vowel reduction into its orthography.


Catalan has seven vowels in stressed syllables and three, four or five vowels in unstressed syllables, depending on dialect. The Valencian dialect has five, as in Vulgar Latin. Majorcan merges unstressed /a/ and /e/, and central Catalan further merges unstressed /o/ and /u/.


Portuguese has seven or eight vowels in stressed syllables (/a, ɐ, ɛ, e, i, ɔ, o, u/). The vowels a and ɐ, which are not phonemically distinct in all dialects, merge in unstressed syllables. In most cases, unstressed syllables may have one of five vowels (/a, e, i, o, u/), but there is a sometimes unpredictable tendency for /e/ to merge with /i/ and /o/ to merge with /u/. For instance some speakers pronounce the first syllable of dezembro ("December") differently from the first syllable of dezoito ("eighteen"), with the latter being more reduced. There are also instances of ɛ and ɔ being distinguished from e and o in unstressed syllables, especially to avoid ambiguity. The verb pregar ("to nail") is distinct from pregar ("to preach"), and the latter verb was historically spelled prègar to reflect that its unstressed ɛ is not reduced.

Portuguese phonology is further complicated by its variety of dialects, particularly the differences between European Portuguese and Brazilian Portuguese, as well as the differences between the respective dialects of the two varieties.

Slavic languages


In the Bulgarian language the vowels а, о and е can be partially or fully reduced, depending on the dialect, when unstressed to ъ, у and и, respectively. The most prevalent is а > ъ, and о > у, which, in its partial form, is considered correct in literary speech. The reduction е > и is prevalent in the eastern dialects of the language and is not considered formally correct.


There are six vowel phonemes in Standard Russian. Vowels tend to merge when they are unstressed. The vowels /a/ and /o/ have the same unstressed allophones for a number of dialects and reduce to a schwa. Unstressed /e/ may become more central if it does not merge with /i/.

Other types of reduction are phonetic, such as that of the high vowels (/i/ and /u/), which become near-close; этап ('stage') is pronounced [ɪˈtap], and мужчина ('man') is pronounced [mʊˈɕːinə].

Early Slavic languages

Proto-Slavic had two short high vowels known as yers: a short high front vowel, denoted as ĭ or ь, and a short back vowel, denoted as ŭ or ъ. Both vowels underwent reduction and were eventually deleted in certain positions in a word in the early Slavic languages, beginning from the late dialects of Proto-Slavic. The process is known as Havlík's law.

See also


  1. A word-play on schwa. [2]
  2. These are imprecise in that the IPA defines ɨ as a close vowel and ɵ as a rounded vowel, neither of which is generally true of the higher reduced vowels.

Related Research Articles

A vowel is a syllabic speech sound pronounced without any stricture in the vocal tract. Vowels are one of the two principal classes of speech sounds, the other being the consonant. Vowels vary in quality, in loudness and also in quantity (length). They are usually voiced and are closely involved in prosodic variation such as tone, intonation and stress.

Schwa Vowel sound as in the first syllable of "about"

In linguistics, specifically phonetics and phonology, schwa is the mid central vowel sound in the middle of the vowel chart, denoted by the IPA symbol, or another vowel sound close to that position. An example in English is the vowel sound of the 〈a〉 in the word about. Schwa in English is mainly found in unstressed positions, but in some other languages it occurs more frequently as a stressed vowel.

In linguistics, and particularly phonology, stress or accent is the relative emphasis or prominence given to a certain syllable in a word or to a certain word in a phrase or sentence. That emphasis is typically caused by such properties as increased loudness and vowel length, full articulation of the vowel, and changes in tone. The terms stress and accent are often used synonymously in that context but are sometimes distinguished. For example, when emphasis is produced through pitch alone, it is called pitch accent, and when produced through length alone, it is called quantitative accent. When caused by a combination of various intensified properties, it is called stress accent or dynamic accent; English uses what is called variable stress accent.

Middle Dutch is a collective name for a number of closely related West Germanic dialects whose ancestor was Old Dutch and was spoken and written between 1150 and 1500. Until the advent of Modern Dutch after 1500, there was no overarching standard language, but all dialects were mutually intelligible. During the period, a rich Medieval Dutch literature developed, which had not yet existed during Old Dutch. The various literary works of the time are often very readable for speakers of Modern Dutch since Dutch is a rather conservative language. Nonlinguists often refer to Middle Dutch as Diets.

Like many other languages, English has wide variation in pronunciation, both historically and from dialect to dialect. In general, however, the regional dialects of English share a largely similar phonological system. Among other things, most dialects have vowel reduction in unstressed syllables and a complex set of phonological features that distinguish fortis and lenis consonants.

French phonology is the sound system of French. This article discusses mainly the phonology of all the varieties of Standard French. Notable phonological features include its uvular r, nasal vowels, and three processes affecting word-final sounds: liaison, a specific instance of sandhi in which word-final consonants are not pronounced unless they are followed by a word beginning with a vowel; elision, in which certain instances of (schwa) are elided ; and enchaînement (resyllabification) in which word-final and word-initial consonants may be moved across a syllable boundary, with syllables crossing word boundaries:

Stress is a prominent feature of the English language, both at the level of the word (lexical stress) and at the level of the phrase or sentence (prosodic stress). Absence of stress on a syllable, or on a word in some cases, is frequently associated in English with vowel reduction – many such syllables are pronounced with a centralized vowel (schwa) or with certain other vowels that are described as being "reduced". Various phonological analyses exist for these phenomena.

R-colored vowel Phonetic sound in some languages

In phonetics, an r-colored or rhotic vowel is a vowel that is modified in a way that results in a lowering in frequency of the third formant. R-colored vowels can be articulated in various ways: the tip or blade of the tongue may be turned up during at least part of the articulation of the vowel or the back of the tongue may be bunched. In addition, the vocal tract may often be constricted in the region of the epiglottis.

In phonetics, clipping is the process of shortening the articulation of a phonetic segment, usually a vowel. A clipped vowel is pronounced more quickly than an unclipped vowel and is often also reduced.

Most dialects of modern English have two close back vowels: the near-close near-back rounded vowel found in words like foot, and the close back rounded vowel found in words like goose. The STRUT vowel, which historically was back, is often central as well. This article discusses the history of these vowels in various dialects of English, focusing in particular on phonemic splits and mergers involving these sounds.

In phonetics and phonology, checked vowels are those that commonly stand in a stressed closed syllable; and free vowels are those that can stand in either a stressed closed syllable or a stressed open syllable.

Akanye or akanje, literally "a-ing", is a sound change in Slavic languages in which the phonemes or are realized as more or less close to. It is a case of vowel reduction.

Dutch phonology is similar to that of other West Germanic languages, especially Afrikaans and West Frisian.

Vowel reduction in Russian differs in the standard language and dialects, which differ from one another. Several ways of vowel reduction are distinguished.

Hindustani is the lingua franca of northern India and Pakistan, and through its two standardized registers, Hindi and Urdu, a co-official language of India and co-official and national language of Pakistan respectively. Phonological differences between the two standards are minimal.

The modern Corsican alphabet uses 22 basic letters taken from the Latin alphabet with some changes, plus some multigraphs. The pronunciations of the English, French, Italian or Latin forms of these letters are not a guide to their pronunciation in Corsu, which has its own pronunciation, often the same, but frequently not. As can be seen from the table below, two of the phonemic letters are represented as trigraphs, plus some other digraphs. Nearly all the letters are allophonic; that is, a phoneme of the language might have more than one pronunciation and be represented by more than one letter. The exact pronunciation depends mainly on word order and usage and is governed by a complex set of rules, variable to some degree by dialect. These have to be learned by the speaker of the language.

The traditional English pronunciation of Latin, and Classical Greek words borrowed through Latin, is the way the Latin language was traditionally pronounced by speakers of English until the early 20th century.

This article discusses the phonological system of Standard Bulgarian. Most scholars agree that contemporary Bulgarian has 45 phonemes but different authors place the real number of Bulgarian phonemes between 42 and 47, depending on whether one includes or excludes phonemes which appear primarily only in borrowed foreign words.

French exhibits perhaps the most extensive phonetic changes of any of the Romance languages. Similar changes are seen in some of the northern Italian regional languages, such as Lombard or Ligurian. Most other Romance languages are significantly more conservative phonetically, with Spanish, Italian, and especially Sardinian showing the most conservatism, and Portuguese, Occitan, Catalan, and Romanian showing moderate conservatism.

This article is about the phonology and phonetics of the Slovene language.


  1. Acoustic vowel reduction in Creek: Effects of distinctive length and position in the word (pdf)
  2. Messum, Piers (2002). "Learning and Teaching Vowels" (PDF). Speak Out! (29): 9–27. Retrieved 2020-09-01.
  3. Bolinger (1986), p. 347.
  4. R. M. Dauer. "Stress-timing and syllable-timing reanalysed". Journal of Phonetics. 11:51–62 (1983).
  5. Eleanor Greet Cotton, John M. Sharp (1988) Spanish in the Americas, Volumen 2, pp.154–155, URL
  6. Lope Blanch, Juan M. (1972) En torno a las vocales caedizas del español mexicano, pp. 53–73, Estudios sobre el español de México, editorial Universidad Nacional Autónoma de México, México URL.