chereme

In phonology and linguistics, a phoneme () is a unit of sound that can distinguish one word from another in a particular language.

For example, in most dialects of English, with the notable exception of the West Midlands and the north-west of England, the sound patterns (''sin'') and (''sing'') are two separate words that are distinguished by the substitution of one phoneme, , for another phoneme, . Two words like this that differ in meaning through the contrast of a single phoneme form a ''minimal pair''. If, in another language, any two sequences differing only by pronunciation of the final sounds or are perceived as being the same in meaning, then these two sounds are interpreted as phonetic variants of a single phoneme in that language.

Phonemes that are established by the use of minimal pairs, such as ''tap'' vs ''tab'' or ''pat'' vs ''bat'', are written between slashes: , . To show pronunciation, linguists use square brackets: (indicating an aspirated ''p'' in ''pat'').

There are differing views as to exactly what phonemes are and how a given language should be analyzed in ''phonemic'' (or ''phonematic'') terms. However, a phoneme is generally regarded as an abstraction of a set (or equivalence class) of speech sounds (''phones'') that are perceived as equivalent to each other in a given language. For example, the English ''k'' sounds in the words ''kill'' and ''skill'' are not identical (as described below), but they are distributional variants of a single phoneme . Speech sounds that differ but do not create a meaningful change in the word are known as ''allophones'' of the same phoneme. Allophonic variation may be conditioned, in which case a certain phoneme is realized as a certain allophone in particular phonological environments, or it may otherwise be free, and may vary by speaker or by dialect. Therefore, phonemes are often considered to constitute an abstract underlying representation for segments of words, while speech sounds make up the corresponding phonetic realization, or the surface form.

Notation

Phonemes are conventionally placed between slashes in transcription, whereas speech sounds (phones) are placed between square brackets. Thus, represents a sequence of three phonemes, , , (the word ''push'' in Standard English), and represents the phonetic sequence of sounds ( aspirated '' p''), , (the usual pronunciation of ''push''). This should not be confused with the similar convention of the use of angle brackets to enclose the units of orthography, graphemes. For example, ⟨f⟩ represents the written letter (grapheme) ''f''.

The symbols used for particular phonemes are often taken from the International Phonetic Alphabet (IPA), the same set of symbols most commonly used for phones. (For computer-typing purposes, systems such as X-SAMPA exist to represent IPA symbols using only ASCII characters.) However, descriptions of particular languages may use different conventional symbols to represent the phonemes of those languages. For languages whose writing systems employ the phonemic principle, ordinary letters may be used to denote phonemes, although this approach is often hampered by the complexity of the relationship between orthography and pronunciation (see below).

Assignment of speech sounds to phonemes

A phoneme is a sound or a group of different sounds perceived to have the same function by speakers of the language or dialect in question. An example is the English phoneme , which occurs in words such as ''cat'', ''kit'', ''scat'', ''skit''. Although most native speakers do not notice this, in most English dialects, the "c/k" sounds in these words are not identical: in , the sound is aspirated, but in , it is unaspirated. The words, therefore, contain different ''speech sounds'', or ''phones'', transcribed for the aspirated form and for the unaspirated one. These different sounds are nonetheless considered to belong to the same phoneme, because if a speaker used one instead of the other, the meaning of the word would not change: using the aspirated form in ''skill'' might sound odd, but the word would still be recognized. By contrast, some other sounds would cause a change in meaning if substituted: for example, substitution of the sound would produce the different word ''still'', and that sound must therefore be considered to represent a different phoneme (the phoneme ).

The above shows that in English, and are allophones of a single phoneme . In some languages, however, and are perceived by native speakers as different sounds, and substituting one for the other can change the meaning of a word. In those languages, therefore, the two sounds represent different phonemes. For example, in Icelandic, is the first sound of , meaning "cheerful", but is the first sound of , meaning "riddles". Icelandic, therefore, has two separate phonemes and .

Minimal pairs

A pair of words like and (above) that differ only in one phone is called a minimal pair for the two alternative phones in question (in this case, and ). The existence of minimal pairs is a common test to decide whether two phones represent different phonemes or are allophones of the same phoneme.

To take another example, the minimal pair ''tip'' and ''dip'' illustrates that in English, and belong to separate phonemes, and ; since both words have different meanings, English-speakers must be conscious of the distinction between the two sounds.

Signed languages, such as American Sign Language (ASL), also have minimal pairs, differing only in (exactly) one of the signs' parameters: handshape, movement, location, palm orientation, and nonmanual signal or marker. A minimal pair may exist in the signed language if the basic sign stays the same, but one of the parameters changes.

However, the absence of minimal pairs for a given pair of phones does not always mean that they belong to the same phoneme: they may be so dissimilar phonetically that it is unlikely for speakers to perceive them as the same sound. For example, English has no minimal pair for the sounds (as in ''hat'') and (as in ''bang''), and the fact that they can be shown to be in complementary distribution could be used to argue for their being allophones of the same phoneme. However, they are so dissimilar phonetically that they are considered separate phonemes.

Phonologists have sometimes had recourse to "near minimal pairs" to show that speakers of the language perceive two sounds as significantly different even if no exact minimal pair exists in the lexicon. It is virtually impossible to find a minimal pair to distinguish English from , yet it seems uncontroversial to claim that the two consonants are distinct phonemes. The two words 'pressure' and 'pleasure' can serve as a near minimal pair.

Suprasegmental phonemes

Besides segmental phonemes such as vowels and consonants, there are also suprasegmental features of pronunciation (such as tone and stress, syllable boundaries and other forms of juncture, nasalization and vowel harmony), which, in many languages, change the meaning of words and so are phonemic.

''Phonemic stress'' is encountered in languages such as English. For example, there are two words spelled ''invite'', one is a verb and is stressed on the second syllable, the other is a noun and stressed on the first syllable (without changing any of the individual sounds). The position of the stress distinguishes the words and so a full phonemic specification would include indication of the position of the stress: for the verb, for the noun. In other languages, such as French, word stress cannot have this function (its position is generally predictable) and so it is not phonemic (and therefore not usually indicated in dictionaries).

''Phonemic tones'' are found in languages such as Mandarin Chinese in which a given syllable can have five different tonal pronunciations:

The tone "phonemes" in such languages are sometimes called ''tonemes''. Languages such as English do not have phonemic tone, but they use intonation for functions such as emphasis and attitude.

Distribution of allophones

When a phoneme has more than one allophone, the one actually heard at a given occurrence of that phoneme may be dependent on the phonetic environment (surrounding sounds). Allophones that normally cannot appear in the same environment are said to be in complementary distribution. In other cases, the choice of allophone may be dependent on the individual speaker or other unpredictable factors. Such allophones are said to be in free variation, but allophones are still selected in a specific phonetic context, not the other way around.

Background and related ideas

The term ''phonème'' (from grc, φώνημα, phōnēma, "sound made, utterance, thing spoken, speech, language"Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press.) was reportedly first used by A. Dufriche-Desgenettes in 1873, but it referred only to a speech sound. The term ''phoneme'' as an abstraction was developed by the Polish linguist Jan 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''. Daniel Jones became the first linguist in the western world to use the term ''phoneme'' in its current sense, employing the word in his article "The phonetic structure of the Sechuana Language". The concept of the phoneme was then elaborated in the works of Nikolai Trubetzkoy 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 (though not Sapir) rejected the idea of a cognitive or psycholinguistic function for the phoneme.

Later, it was used and redefined in generative linguistics, most famously by Noam Chomsky and Morris Halle, and remains central to many accounts of the development of modern phonology. As a theoretical concept or model, though, it has been supplemented and even replaced by others.

Some linguists (such as Roman Jakobson) proposed that phonemes may 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 characterized in different ways: Jakobson and colleagues defined them in acoustic terms, Chomsky and Halle used a predominantly articulatory basis, though retaining some acoustic features, while Ladefoged's system is a purely articulatory system apart from the use of the acoustic term 'sibilant'.

In the description of some languages, the term chroneme has been used to indicate contrastive length or ''duration'' of phonemes. In languages in which tones are phonemic, the tone phonemes may be called tonemes. Though not all scholars working on such languages use these terms, they are by no means obsolete.

By analogy with the phoneme, linguists have proposed other sorts of underlying objects, giving them names with the suffix ''-eme'', such as ''morpheme'' and ''grapheme''. These are sometimes called emic units. The latter term was first used by Kenneth Pike, who also generalized the concepts of emic and etic description (from ''phonemic'' and ''phonetic'' respectively) to applications outside linguistics.

Restrictions on occurrence

Languages do not generally allow words or syllables to be built of any arbitrary sequences of phonemes. There are phonotactic restrictions on which sequences of phonemes are possible and in which environments certain phonemes can occur. Phonemes that are significantly limited by such restrictions may be called ''restricted phonemes''.

In English, examples of such restrictions include the following:

* , as in ''sing'', occurs only at the end of a syllable, never at the beginning (in many other languages, such as Māori, Swahili, Tagalog, and Thai, can appear word-initially).
* occurs only at the beginning of a syllable, never at the end (a few languages, such as Arabic and Romanian, allow syllable-finally).
* In non-rhotic dialects, can occur immediately only before a vowel, never before a consonant.
* and occur only before a vowel, never at the end of a syllable (except in interpretations in which a word like ''boy'' is analyzed as ).

Some phonotactic restrictions can alternatively be analyzed as cases of neutralization. See Neutralization and archiphonemes below, particularly the example of the occurrence of the three English nasals before stops.

Biuniqueness

Biuniqueness is a requirement of classic structuralist phonemics. It means that a given phone, wherever it occurs, must unambiguously be assigned to one and only one phoneme. In other words, the mapping between phones and phonemes is required to be many-to-one rather than many-to-many. 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.

An example of the problems arising from the biuniqueness requirement is provided by the phenomenon of flapping in North American English. This may cause either or (in the appropriate environments) to be realized with the phone (an alveolar flap). For example, the same flap sound may be heard in the words ''hitting'' and ''bidding'', although it is intended to realize the phoneme in the first word and in the second. This appears to contradict biuniqueness.

For further discussion of such cases, see the next section.

Neutralization and archiphonemes

Phonemes that are contrastive in certain environments may not be contrastive in all environments. In the environments where they do not contrast, the contrast is said to be neutralized. In these positions it may become less clear which phoneme a given phone represents. Absolute neutralization is a phenomenon in which a segment of the underlying representation is not realized in any of its phonetic