Allophone

[1] For example, in English, the voiceless plosive [t] (as in stop [ˈstɒp]) and the aspirated form [tʰ] (as in top [ˈtʰɒp]) are allophones for the phoneme /t/,[citation needed] while these two are considered to be different phonemes in some languages such as Central Thai.

[4] The term was popularized by George L. Trager and Bernard Bloch in a 1941 paper on English phonology[5] and went on to become part of standard usage within the American structuralist tradition.

Each allophone from a complementary set is used in a specific phonetic context and may be involved in a phonological process.

English-speakers may be unaware of differences between a number of (dialect-dependent) allophones of the phoneme /t/: In addition, the following allophones of /t/ are found in (at least) some dialects of American(ised) English; However, speakers may become aware of the differences if – for example – they contrast the pronunciations of the following words: A flame that is held in front of the lips while those words are spoken flickers more for the aspirated nitrate than for the unaspirated night rate.

Peter Ladefoged, a renowned phonetician, clearly explains the consonant allophones of English in a precise list of statements to illustrate the language behavior.

Typically, languages with a small phoneme inventory allow for quite a lot of allophonic variation: examples are Hawaiian and Pirahã.

Often, if only one of the allophones is simple to transcribe, in the sense of not requiring diacritics, that representation is chosen for the phoneme.

In rare cases, a linguist may represent phonemes with abstract symbols, such as dingbats, to avoid privileging any particular allophone.