Phonemewikipedia
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.
phonemephonemicphonemesphonemicallyarchiphonemeneutralizedneutralizationsoundsarchiphonemicsound

Allophone

allophoneallophonicallophones
Different speech sounds that are realizations of the same phoneme are known as allophones.
In phonology, an allophone (from the Greek ἄλλος, állos, "other" and φωνή, phōnē, "voice, sound") is one of a set of multiple possible spoken sounds, or phones, or signs used to pronounce a single phoneme in a particular language.

Minimal pair

minimal pairminimal pairssplit
(Two words like this that differ in meaning through a contrast of a single phoneme form what is called a minimal pair).
In phonology, minimal pairs are pairs of words or phrases in a particular language, spoken or signed, that differ in only one phonological element, such as a phoneme, toneme or chroneme, and have distinct meanings.

Phonemic orthography

phonemic orthographyphonetic spellingphonemic
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).
In linguistics, a phonemic orthography is an orthography (system for writing a language) in which the graphemes (written symbols) correspond to the phonemes (significant spoken sounds) of the language.

Grapheme

graphemegraphemescharacters
This is not to be confused with the similar convention of the use of angle brackets to enclose the units of orthography, namely graphemes; for example, ⟨f⟩ represents the written letter (grapheme) f.
An individual grapheme may or may not carry meaning by itself, and may or may not correspond to a single phoneme of the spoken language.

International Phonetic Alphabet

IPAPronunciationdiacritic
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.
The IPA is designed to represent only those qualities of speech that are part of oral language: phones, phonemes, intonation and the separation of words and syllables.

Tone (linguistics)

tonetonal languagetones
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.
Languages that do have this feature are called tonal languages; the distinctive tone patterns of such a language are sometimes called tonemes, by analogy with phoneme.

Phone (phonetics)

phonesphonespeech sound
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.
In contrast, a phoneme is a speech sound in a given language that, if swapped with another phoneme, would change the meaning of the word.

Jan Baudouin de Courtenay

Baudouin de CourtenayBaudoinBaudouin de Courtenay, Jan Niecisław
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.
Jan Niecisław Ignacy Baudouin de Courtenay (13 March 1845 – 3 November 1929) was a Polish linguist and Slavist, best known for his theory of the phoneme and phonetic alternations.

Free variation

free variationfreely variesfree variants
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.
When phonemes are in free variation, speakers are sometimes strongly aware of the fact (especially if such variation is noticeable only across a dialectal or sociolectal divide), and will note, for example, that tomato is pronounced differently in British and American English (/təˈmɑːˌtəʊ/ and /təˈmeɪˌtoʊ/ respectively), or that either has two pronunciations that are distributed fairly randomly.

Phonology

phonologyphonologicalphonologically
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.
It has traditionally focused largely on the study of the systems of phonemes in particular languages (and therefore used to be also called phonemics, or phonematics), but it may also cover any linguistic analysis either at a level beneath the word (including syllable, onset and rime, articulatory gestures, articulatory features, mora, etc.) or at all levels of language where sound is considered to be structured for conveying linguistic meaning.

Chroneme

chronemelength
In the description of some languages, the term chroneme has been used to indicate contrastive length or duration of phonemes.
The noun chroneme is derived from Greek χρόνος (chrónos, time), and the suffixed -eme, which is analogous to the -eme in phoneme or morpheme.

Cherology

cheremecherologycheremic
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.
Cherology and chereme (from "hand") are synonyms of phonology and phoneme previously used in the study of sign languages.

Orthography

orthographyorthographicorthographies
This is not to be confused with the similar convention of the use of angle brackets to enclose the units of orthography, namely graphemes; for example, ⟨f⟩ represents the written letter (grapheme) f.
Orthography is largely concerned with matters of spelling, and in particular the relationship between phonemes and graphemes in a language.

Emic unit

emic unitunitEmic and etic units
These are sometimes called emic units.
Kinds of emic units are generally denoted by terms with the suffix -eme, such as phoneme, grapheme, and morpheme.

Edward Sapir

SapirSapir, EdwardEdward Sapir
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.
He played an important role in developing the modern concept of the phoneme, greatly advancing the understanding of phonology.

Linguistics

linguisticslinguistlinguistic
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).

Phonotactics

phonotacticsphonotacticphonotactical
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.
Phonotactics (from Ancient Greek phōnḗ "voice, sound" and tacticós "having to do with arranging") is a branch of phonology that deals with restrictions in a language on the permissible combinations of phonemes.

Structural linguistics

structural linguisticsstructuraliststructuralism
Biuniqueness is a requirement of classic structuralist phonemics.
Structural linguistics involves collecting a corpus of utterances and then attempting to classify all of the elements of the corpus at their different linguistic levels: the phonemes, morphemes, lexical categories, noun phrases, verb phrases, and sentence types.

Bracket

parenthesesbracketparenthesis
This is not to be confused with the similar convention of the use of angle brackets to enclose the units of orthography, namely graphemes; for example, ⟨f⟩ represents the written letter (grapheme) f. 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.
In linguistics, phonetic transcriptions are generally enclosed within brackets, often using the International Phonetic Alphabet, whereas phonemic transcriptions typically use paired slashes.

Taa language

Taa!XóõǃXóõ
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.
Taa, also known as ǃXóõ (ǃKhong, ǃXoon – pronounced, ), is a Tuu language notable for its large number of phonemes, perhaps the largest in the world.

Flapping

flappingintervocalic alveolar flappingflapped
An example of the problems arising from the biuniqueness requirement is provided by the phenomenon of flapping in North American English.
Flapping or tapping, also known as alveolar flapping, intervocalic flapping, or t-voicing, is a phonological process found in many dialects of English, especially North American English, Australian English and New Zealand English, by which the consonant phoneme or placed between vowels is pronounced as a voiced flap under certain conditions.

Ubykh language

Ubykhubylinguistically
The number of phonemically distinct vowels can be as low as two, as in Ubykh and Arrernte.
The Ubykh language is ergative and polysynthetic, with a high degree of agglutination, with polypersonal verbal agreement and a very large number of distinct consonants but only two phonemically distinct vowels.

Pirahã language

Pirahãtheir languageIndigenous language of Pirahans
The total phonemic inventory in languages varies from as few as 11 in Rotokas and Pirahã to as many as 141 in !Xũ.
There is a claim that Pirahã has as few as ten phonemes, one fewer than Rotokas, but this requires analyzing as an underlying.

Rotokas language

Rotokastheir languageroo
The total phonemic inventory in languages varies from as few as 11 in Rotokas and Pirahã to as many as 141 in !Xũ.
Central Rotokas is most notable for its extremely small phonemic inventory and for having perhaps the smallest modern alphabet.

Aspirated consonant

aspiratedaspirationunaspirated
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).
In many languages, such as Armenian, Korean, Lakota, Thai, Indo-Aryan languages, Dravidian languages, Icelandic, Ancient Greek, and the varieties of Chinese, tenuis and aspirated consonants are phonemic.