In human
language, a
phoneme (from the
Greek f???µa,
phonema, "a sound uttered") is the smallest posited structural unit that distinguishes
meaning. Phonemes are not the physical
segments themselves, but, in theoretical terms, cognitive
abstractions or categorizations of them.
An example of a phoneme is the /t/ sound in the words tip, stand, water, and cat. (In transcription, phonemes are placed between slashes, as here.) These instances of /t/ are considered to fall under the same sound category despite the fact that in each word they are pronounced somewhat differently. The difference may not even be audible to native speakers, or the audible differences not perceived. That is, a phoneme may encompass several recognizably different speech sounds, called phones. In our example, the /t/ in tip is aspirated, [t?], while the /t/ in stand is not, [t]. (In transcription, speech sounds that are not phonemes are placed in brackets, as here.) In many languages, such as Korean and Spanish, these phones are different phonemes For example, /tol/ is "stone" in Korean, whereas /t?ol/ is "grain of rice". In Spanish, there is no aspirated [t?], but the phone in American English writer is similar to the Spanish r /?/ and contrasts with Spanish /t/.
Phones that belong to the same phoneme, such as [t] and [t?] 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 (/t?ata/ is pronounced [t?ada], for example) indicates that in this language they are allophones of a phoneme /t/.
In sign languages, the basic elements of gesture and location were formerly called cheremes (or cheiremes), but general usage changed to phoneme. Tonic phonemes are sometimes called tonemes, and timing phonemes chronemes.
