Phoneme

A phoneme is one of the units of sound (or gesture in the case of sign languages, see chereme) that distinguish one word from another in a particular language. For example, in most dialects of English, the sound patterns (thin) and  (din) are two separate words distinguished by the substitution of one phoneme,, for another phoneme,. (Two words like this that differ in meaning through a contrast of a single phoneme form what is called a minimal pair). In many other languages, e.g. Spanish, these would be interpreted as exactly the same set of phonemes (i.e. and  would be considered the same).

In linguistics, phonemes (usually established by the use of minimal pairs, such as kill vs kiss or pat vs bat) are written between slashes, e.g. . To show pronunciation more precisely linguists use square brackets, for example (indicating an aspirated p).

Within linguistics 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) which are perceived as equivalent to each other in a given language. For example, in English, the k sounds in the words kit and skill are not identical (as described below), but they are distributional variants of a single phoneme. Different speech sounds that are realizations of the same phoneme are known as allophones. Allophonic variation may be conditioned, in which case a certain phoneme is realized as a certain allophone in particular phonological environments, or it may be free in which case it may vary randomly. In this way, phonemes are often considered to constitute an abstract underlying representation for segments of words, while speech sounds make up the corresponding phonetic realization, or 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), while  represents the phonetic sequence of sounds  (aspirated p), ,  (the usual pronunciation of push). (Another similar convention is the use of angle brackets to enclose the units of orthography, namely 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 that are most commonly used for phones. (For computer typing purposes, systems such as X-SAMPA and Kirshenbaum 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 Correspondence between letters and phonemes 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, while in   it is unaspirated. The words therefore contain different speech sounds, or phones, transcribed for the aspirated form,  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; this means that in those languages, the two sounds represent different phonemes. For example, in Icelandic, is the first sound of kátur meaning "cheerful", while  is the first sound of gátur meaning "riddles". Icelandic therefore has two separate phonemes and.

Minimal pairs
A pair of words like kátur and gátur (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 these two words have different meanings, English speakers must be conscious of the distinction between the two sounds. In other languages, though, including Korean, even though both sounds and  occur, no such minimal pair exists. The lack of minimal pairs distinguishing and  in Korean provides evidence that in this language they are allophones of a single phoneme. The word is pronounced, for example. That is, when they hear this word, Korean speakers perceive the same sound in both the beginning and middle of the word, whereas an English speaker would perceive different sounds in these two locations. 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 non-manual signal or marker. A minimal pair may exist in the signed language if the basic sign stays the same but one of these 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 too dissimilar phonetically for it to be likely that speakers 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.

Other features with phonemic status
While phonemes are normally conceived of as abstractions of discrete segmental speech sounds (vowels and consonants), there are other features of pronunciation – principally tone and stress – which in some languages can change the meaning of words in the way that phoneme contrasts do, and are consequently called phonemic features of those languages.

Phonemic stress is encountered in languages such as English. For example, the word invite stressed on the second syllable is a verb, but when stressed on the first syllable (without changing any of the individual sounds) it becomes a noun. The position of the stress in the word affects the meaning, and therefore a full phonemic specification (providing enough detail to enable the word to be pronounced unambiguously) 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 is therefore not phonemic (and is 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.

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 which 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.

Background and related ideas
The term phonème (from Ancient Greek φώνημα phōnēma, "sound made, utterance, thing spoken, speech, language" ) 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 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 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 and Morris Halle) 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. Examples of such restrictions in English include:


 * , 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 before vowels and at the beginning of a syllable, never at the end (a few languages, such as Arabic, or Romanian allow syllable-finally).
 * In non-rhotic dialects, can only occur immediately before a vowel, never before a consonant.
 * and occur only before a vowel, never at the end of a syllable (except in interpretations where 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 clearly 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. Some phonologists prefer not to specify a unique phoneme in such cases, since to do so would mean providing redundant or even arbitrary information – instead they use the technique of underspecification. An archiphoneme is an object sometimes used to represent an underspecified phoneme.

An example of neutralization is provided by the Russian vowels and. These phonemes are contrasting in stressed syllables, but in unstressed syllables the contrast is lost, since both are reduced to the same sound, usually (for details, see vowel reduction in Russian). In order to assign such an instance of to one of the phonemes  and, it is necessary to consider morphological factors (such as which of the vowels occurs in other forms of the words, or which inflectional pattern is followed). In some cases even this may not provide an unambiguous answer. A description using the approach of underspecification would not attempt to assign to a specific phoneme in some or all of these cases, although it might be assigned to an archiphoneme, written something like |A|, which reflects the two neutralized phonemes in this position.

A somewhat different example is found in English, with the three nasal phonemes. In word-final position these all contrast, as shown by the minimal triplet sum, sun , sung. However, before a stop such as (provided there is no morpheme boundary between them), only one of the nasals is possible in any given position:  before,  before  or , and  before , as in limp, lint, link. The nasals are therefore not contrastive in these environments, and according to some theorists this makes it inappropriate to assign the nasal phones heard here to any one of the phonemes (even though, in this case, the phonetic evidence is unambiguous). Instead they may analyze these phones as belonging to a single archiphoneme, written something like |N|, and state the underlying representations of limp, lint, link to be.

This latter type of analysis is often associated with Nikolai Trubetzkoy of the Prague school. Archiphonemes are often notated with a capital letter within pipes, as with the examples |A| and |N| given above. Other ways the second of these might be notated include, , or |n*|.

Another example from English, but this time involving complete phonetic convergence as in the Russian example, is the flapping of and  in some American English (described above under Biuniqueness). Here the words betting and bedding might both be pronounced, and if a speaker applies such flapping consistently, it would be necessary to look for morphological evidence (the pronunciation of the related forms bet and bed, for example) in order to determine which phoneme the flap represents. As in the previous examples, some theorists would prefer not to make such a determination, and simply assign the flap in both cases to a single archiphoneme, written (for example) |D|.

For a special kind of neutralization proposed in generative phonology, see absolute neutralization.

Morphophonemes
A morphophoneme is a theoretical unit at a deeper level of abstraction than traditional phonemes, and is taken to be a unit from which morphemes are built up. A morphophoneme within a morpheme can be expressed in different ways in different allomorphs of that morpheme (according to morphophonological rules). For example, the English plural morpheme -s appearing in words such as cats and dogs can be considered to consist of a single morphophoneme, which might be written (for example) //z// or |z|, and which is pronounced as [s] after most voiceless consonants (as in cats) and [z] in most other cases (as in dogs).

Numbers of phonemes in different languages
A given language will use only a small subset of the many possible sounds that the human speech organs can produce, and (because of allophony) the number of distinct phonemes will generally be smaller than the number of identifiably different sounds. Different languages vary considerably in the number of phonemes they have in their systems (although apparent variation may sometimes result from the different approaches taken by the linguists doing the analysis). The total phonemic inventory in languages varies from as few as 11 in Rotokas and Pirahã to as many as 141 in !Xũ.

The number of phonemically distinct vowels can be as low as two, as in Ubykh and Arrernte. At the other extreme, the Bantu language Ngwe has 14 vowel qualities, 12 of which may occur long or short, making 26 oral vowels, plus 6 nasalized vowels, long and short, making a total of 38 vowels; while !Xóõ achieves 31 pure vowels, not counting its additional variation by vowel length, by varying the phonation. As regards consonant phonemes, Puinave and the Papuan language Tauade each have just seven, and Rotokas has only six. !Xóõ, on the other hand, has somewhere around 77, and Ubykh 81. The English language uses a rather large set of 13 to 21 vowel phonemes, including diphthongs, although its 22 to 26 consonants are close to average.

Some languages, such as French, have no phonemic tone or stress, while Cantonese and several of the Kam–Sui languages have nine tones, and one of the Kru languages, Wobe, has been claimed to have 14, though this is disputed.

The most common vowel system consists of the five vowels. The most common consonants are. Relatively few languages lack any of these consonants, although it does happen: for example, Arabic lacks, standard Hawaiian lacks , Mohawk and Tlingit lack and , Hupa lacks both  and a simple , colloquial Samoan lacks  and , while Rotokas and Quileute lack  and.

Correspondence between letters and phonemes
Phonemes are considered to be the basis for alphabetic writing systems. In such systems the written symbols (graphemes) represent, in principle, the phonemes of the language being written. This is most obviously the case when the alphabet was invented with a particular language in mind; for example, the Latin alphabet was devised for Classical Latin, and therefore the Latin of that period enjoyed a near one-to-one correspondence between phonemes and graphemes in most cases, though the devisers of the alphabet chose not to represent the phonemic effect of vowel length. However, because changes in the spoken language are often not accompanied by changes in the established orthography (as well as other reasons, including dialect differences, the effects of morphophonology on orthography, and the use of foreign spellings for some loanwords), the correspondence between spelling and pronunciation in a given language may be highly distorted; this is the case with English, for example.

The correspondence between symbols and phonemes in alphabetic writing systems is not necessarily a one-to-one correspondence. A phoneme might be represented by a combination of two or more letters (digraph, trigraph, etc.), like &lt;sh&gt; in English or &lt;sch&gt; in German (both representing phonemes ). Also a single letter may represent two phonemes, as in English &lt;x&gt; representing /gz/ or /ks/. There may also exist spelling/pronunciation rules (such as those for the pronunciation of &lt;c&gt; in Italian) that further complicate the correspondence of letters to phonemes, although they need not affect the ability to predict the pronunciation from the spelling and vice versa, provided the rules are known.

Phonemes in sign languages
In sign languages, the basic elements of gesture and location were formerly called cheremes or cheiremes but they are now generally referred to as phonemes, as with oral languages.

Sign language phonemes are combinations of articulation bundles in ASL. These bundles may be classified as tab (elements of location, from Latin tabula), dez (the hand shape, from designator), sig (the motion, from signation), and with some researchers, ori (orientation). Facial expression and mouthing are also considered articulation bundles. Just as with spoken languages, when these bundles are combined, they create phonemes.

Stokoe notation is no longer used by researchers to denote the phonemes of sign languages; his research, while still considered seminal, has been found to not describe American Sign Language and cannot be used interchangeably with other signed languages. Originally developed for American Sign Language, it has also been applied to British Sign Language by Kyle and Woll, and to Australian Aboriginal sign languages by Adam Kendon. Other sign notations, such as the Hamburg Notation System and SignWriting, are phonetic scripts capable of writing any sign language. Stokoe's work has been succeeded and improved upon by researcher Scott Liddell in his book Grammar, Gesture, and Meaning in American Sign Language, and both Stokoe and Liddell's work have been included in Linguistics of American Sign Language, 5th Edition.