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In a language or dialect, a phoneme (from the Greek: φώνημα, phōnēma, "a sound uttered") is the smallest segmental unit of sound employed to form meaningful contrasts between utterances.
Thus a phoneme is a group of slightly different sounds which are all perceived to have the same function by speakers of the language or dialect in question. An example of a phoneme is the /k/ sound in the words kit and skill. (In transcription, phonemes are placed between slashes, as here.) Even though most native speakers don't notice this, in most dialects, the k sounds in each of these words are actually pronounced differently: they are different speech sounds, or phones (which, in transcription, are placed in square brackets). In our example, the /k/ in kit is aspirated, [kʰ], while the /k/ in skill is not, [k]. The reason why these different sounds are nonetheless considered to belong to the same phoneme in English is that if an English-speaker used one instead of the other, the meaning of the word would not change: saying [kʰ] in skill might sound odd, but the word would still be recognized. By contrast, some other sounds could be substituted which would cause a change in meaning, producing words like still (substituting /t/), spill (substituting /p/) and swill (substituting /w/). These other sounds (/t/, /p/ and /w/) are, in English, different phonemes. In some languages, however, [kʰ] and [k] are different phonemes, and are perceived as such by the speakers of those languages. Thus, in Icelandic, /kʰ/ is the first sound of kátur 'cheerful', while /k/ is the first sound of gátur 'riddles'.
In some languages, each letter in the spelling system represents one phoneme. However, in English spelling there is a poor match between spelling and phonemes. For example, the two letters sh represent the single phoneme /ʃ/, while the letters k and c can both represent the phoneme /k/ (as in kit and cat).
Phones that belong to the same phoneme, such as [t] and [tʰ] for English /t/, are called allophones. A common test to determine whether two phones are allophones or separate phonemes relies on finding minimal pairs: words that differ by only the phones in question. For example, the words tip and dip illustrate that [t] and [d] are separate phonemes, /t/ and /d/, in English, whereas the lack of such a contrast in Korean (/tʰata/ is pronounced [tʰada], for example) indicates that in this language they are allophones of a phoneme /t/.
Some linguists (such as Roman Jakobson, Morris Halle, and Noam Chomsky) consider phonemes to be further decomposable into features, such features being the true minimal constituents of language. Features overlap each other in time, as do suprasegmental phonemes in oral language and many phonemes in sign languages. Features could be designated as acoustic (Jakobson) or articulatory (Halle & Chomsky) in nature.
The term phonème was reportedly first used by A. Dufriche-Desgenettes in 1873, but it referred only to a sound of speech. The term phoneme as an abstraction was developed by the Polish linguist Jan Niecisław Baudouin de Courtenay and his student Mikołaj Kruszewski during 1875-1895. The term used by these two was fonema, the basic unit of what they called psychophonetics. The concept of the phoneme was then elaborated in the works of Nikolai Trubetzkoi and others of the Prague School (during the years 1926-1935), and in those of structuralists like Ferdinand de Saussure, Edward Sapir, and Leonard Bloomfield. Some structuralists wished to eliminate a cognitive or psycholinguistic function for the phoneme.
Later, it was also used in generative linguistics, most famously by Noam Chomsky and Morris Halle, and remains central to many accounts of the development of modern of phonology. As a theoretical concept or model, though, it has been supplemented and even replaced by others.
Some languages make use of tone for phonemic distinction. In this case, the tones used are called tonemes. Some languages distinguish words made up of the same phonemes (and tonemes) by using different durations of some elements, which are called chronemes. However, not all scholars working on languages with distinctive duration use this term.
The distinction between phonetic and phonemic systems gave rise of Kenneth Pike's concepts of Emic and etic description.
Notation
A transcription that only indicates the different phonemes of a language is said to be phonemic. In languages that are morphophonemic (vowels in particular)[clarification needed], pronunciations that correspond to the canonical alphabet pronunciations are called alphaphonemic. Such transcriptions are enclosed within virgules (slashes), / /; these show that each enclosed symbol is claimed to be phonemically meaningful. On the other hand, a transcription that indicates finer detail, including allophonic variation like the two English L's, is said to be phonetic, and is enclosed in square brackets, [ ].
The common notation used in linguistics employs virgules (slashes) (/ /) around the symbol that stands for the phoneme. For example, the phoneme for the initial consonant sound in the word "phoneme" would be written as /f/. In other words, the graphemes are <ph>, but this digraph represents one sound /f/. Allophones, more phonetically specific descriptions of how a given phoneme might be commonly instantiated, are often denoted in linguistics by the use of diacritical or other marks added to the phoneme symbols and then placed in square brackets ([ ]) to differentiate them from the phoneme in slant brackets (/ /). The conventions of orthography are then kept separate from both phonemes and allophones by the use of angle brackets < > to enclose the spelling.
The symbols of the International Phonetic Alphabet (IPA) and extended sets adapted to a particular language are often used by linguists to write phonemes of oral languages, with the principle being one symbol equals one categorical sound. Due to problems displaying some symbols in the early days of the Internet, systems such as X-SAMPA and Kirshenbaum were developed to represent IPA symbols in plain text. As of 2004, any modern web browser can display IPA symbols (as long as the operating system provides the appropriate fonts), and we use this system in this article.
Usually, long vowels and consonants are represented either by a length indicator or doubling of the symbol in question.
Examples
Examples of phonemes in the English language include consonant sounds like /p/ and /b/. These two are most often written consistently with one letter for each sound. However, phonemes might not be so apparent in written English, for example when they are typically represented by a group of more than one letter, called a digraph, like <sh> (pronounced /ʃ/) or <ch> (pronounced /tʃ/).
For a list of the phonemes in the English language, see IPA for English.
Two sounds which are allophones (sound variants belonging to the same phoneme) in one language may belong to separate phonemes in another language or dialect. In English, for example, /p/ has aspirated and non-aspirated allophones:aspirated as in /pɪn/, and non-aspirated as in /spɪn/. However, in many languages (e. g. Chinese), aspirated /pʰ/ is a phoneme distinct from unaspirated /p/. As another example, there is no distinction between [r] and [l] in Japanese: there is only one /r/ phoneme, though it has various allophones that can sound more like [l], [ɾ], or [r] to English speakers. The sounds [z] and [s] are distinct phonemes in English, but allophones in some variants of Spanish like 'andaluz'. The sounds [n] (as in run) and [ŋ] (as in rung) are phonemes in English, but allophones in Italian and Spanish.
An important phoneme is the chroneme, a phonemically-relevant extension of the duration of a consonant or vowel. Some languages or dialects such as Finnish or Japanese allow chronemes after both consonants and vowels. Others, like Australian English use it after only one (in the case of Australian, vowels).
Restricted phonemes
A restricted phoneme is a phoneme that can only occur in a certain environment: There are restrictions as to where it can occur. English has several restricted phonemes:
- /ŋ/, as in sing, occurs only at the end of a syllable, never at the beginning (in many other languages, such as Swahili or Thai, /ŋ/ can appear word-initially).
- /h/ occurs only before vowels and at the beginning of a syllable, never at the end (a few languages, such as Arabic, or Romanian allow /h/ syllable-finally).
- In many American dialects with the cot-caught merger, /ɔ/ occurs only before /r/, /l/, and in the diphthong /ɔɪ/.
- In non-rhotic dialects, /r/ can only occur before a vowel, never at the end of a word or before a consonant.
- Under most interpretations, /w/ and /j/ occur only before a vowel, never at the end of a syllable. However, many phonologists interpret a word like boy as either /bɔɪ/ or /bɔj/.
Biuniqueness
This section requires expansion.
Biuniqueness is a property of the phoneme in classic structuralist phonemics. The biuniqueness definition states that every phonetic allophone must unambiguously be assigned to one and only one phoneme. In other words, there is a many-to-one allophone-to-phoneme mapping instead of a many-to-many mapping.
The notion of biuniqueness was controversial among some pre-generative linguists and was prominently challenged by Morris Halle and Noam Chomsky in the late 1950s and early 1960s.
The unworkable aspects of the concept soon become apparent if you consider the phenomenon of flapping in North American English. In the right environment, this flapping can change either /t/ or /d/ into the allophone [ɾ] for many affected speakers. Here, one allophone is clearly assigned to two phonemes.
Neutralization, archiphoneme, underspecification
Phonemes that are contrastive in certain environments may not be contrastive in all environments. In the environments where they don't contrast, the contrast is said to be neutralized.
In English there are three nasal phonemes, /m, n, ŋ/, as shown by the minimal triplet,
/sʌm/ sum/sʌn/ sun
/sʌŋ/ sung
However, with rare exceptions, these sounds are not contrastive before plosives such as /p, t, k/ within the same morpheme. Although all three phones appear before plosives, for example in limp, lint, link, only one of these may appear before each of the plosives. That is, the /m, n, ŋ/ distinction is neutralized before each of the plosives /p, t, k/:
- Only /m/ occurs before /p/,
- only /n/ before /t/, and
- only /ŋ/ before /k/.
Thus these phonemes are not contrastive in these environments, and according to some theorists, there is no evidence as to what the underlying representation might be. If we hypothesize that we are dealing with only a single underlying nasal, there is no reason to pick one of the three phonemes /m, n, ŋ/ over the other two.
(In some languages there is only one phonemic nasal anywhere, and due to obligatory assimilation, it surfaces as [m, n, ŋ] in just these environments, so this idea is not as far-fetched as it might seem at first glance.)
In certain schools of phonology, such a neutralized distinction is known as an archiphoneme (Nikolai Trubetzkoy of the Prague school is often associated with this analysis). Archiphonemes are often notated with a capital letter. Following this convention, the neutralization of /m, n, ŋ/ before /p, t, k/ could be notated as |N|, and limp, lint, link would be represented as |lɪNp, lɪNt, lɪNk|. (The |pipes| indicate underlying representation.) Other ways this archiphoneme could be notated are |m-n-ŋ|, {m, n, ŋ}, or |n*|.
Another example from American English is the neutralization of the plosives /t, d/ following a stressed syllable. Phonetically, both are realized in this position as [ɾ], a voiced alveolar flap. This can be heard by comparing writer with rider (for the sake of simplicity, Canadian raising is not taken into account).