Aspiration (phonetics)

In phonetics, aspiration is the strong burst of breath that accompanies either the release or, in the case of preaspiration, the closure of some obstruents. In English, aspirated consonants are allophones in complementary distribution with their unaspirated counterparts, but in some other languages, notably most South Asian languages (including Indian) and East Asian languages, the difference is contrastive.

In dialects with aspiration, to feel or see the difference between aspirated and unaspirated sounds, one can put a hand or a lit candle in front of one's mouth, and say ''spin'' and then ''pin'' . One should either feel a puff of air or see a flicker of the candle flame with ''pin'' that one does not get with ''spin''.

Transcription

In the International Phonetic Alphabet (IPA), aspirated consonants are written using the symbols for voiceless consonants followed by the aspiration modifier letter , a superscript form of the symbol for the voiceless glottal fricative . For instance, represents the voiceless bilabial stop, and represents the aspirated bilabial stop.

Voiced consonants are seldom actually aspirated. Symbols for voiced consonants followed by , such as , typically represent consonants with murmured voiced release (see below). In the grammatical tradition of Sanskrit, aspirated consonants are called voiceless aspirated, and breathy-voiced consonants are called voiced aspirated.

There are no dedicated IPA symbols for degrees of aspiration and typically only two degrees are marked: unaspirated and aspirated . An old symbol for light aspiration was , but this is now obsolete. The aspiration modifier letter may be doubled to indicate especially strong or long aspiration. Hence, the two degrees of aspiration in Korean stops are sometimes transcribed or and , but they are usually transcribed and , with the details of voice onset time given numerically.

Preaspirated consonants are marked by placing the aspiration modifier letter before the consonant symbol: represents the preaspirated bilabial stop.

Unaspirated or tenuis consonants are occasionally marked with the modifier letter for unaspiration , a superscript equals sign: . Usually, however, unaspirated consonants are left unmarked: .

Phonetics

Voiceless consonants are produced with the vocal folds open (spread) and not vibrating, and voiced consonants are produced when the vocal folds are fractionally closed and vibrating (modal voice). Voiceless aspiration occurs when the vocal folds remain open after a consonant is released. An easy way to measure this is by noting the consonant's voice onset time, as the voicing of a following vowel cannot begin until the vocal folds close.

In some languages, such as Navajo, aspiration of stops tends to be phonetically realised as voiceless velar airflow; aspiration of affricates is realised as an extended length of the frication.

Aspirated consonants are not always followed by vowels or other voiced sounds. For example, in Eastern Armenian, aspiration is contrastive even word-finally, and aspirated consonants occur in consonant clusters. In Wahgi, consonants are aspirated only when they are in final position.

Degree

The degree of aspiration varies: the voice onset time of aspirated stops is longer or shorter depending on the language or the place of articulation.

Armenian and Cantonese have aspiration that lasts about as long as English aspirated stops, in addition to unaspirated stops. Korean has lightly-aspirated stops that fall between the Armenian and Cantonese unaspirated and aspirated stops as well as strongly-aspirated stops whose aspiration lasts longer than that of Armenian or Cantonese. (See voice onset time.)

Aspiration varies with place of articulation. The Spanish voiceless stops have voice onset times (VOTs) of about 5, 10, and 30 milliseconds, and English aspirated have VOTs of about 60, 70, and 80 ms. Voice onset time in Korean has been measured at 20, 25, and 50 ms for and 90, 95, and 125 for .

Doubling

When aspirated consonants are doubled or geminated, the stop is held longer and then has an aspirated release. An aspirated affricate consists of a stop, fricative, and aspirated release. A doubled aspirated affricate has a longer hold in the stop portion and then has a release consisting of the fricative and aspiration.

Preaspiration

Icelandic and Faroese have consonants with preaspiration , and some scholars interpret them as consonant clusters as well. In Icelandic, preaspirated stops contrast with double stops and single stops:

Preaspiration is also a feature of Scottish Gaelic:

Preaspirated stops also occur in most Sami languages. For example, in Northern Sami, the unvoiced stop and affricate phonemes , , , , are pronounced preaspirated (, , , ) in medial or final position.

Fricatives and sonorants

Although most aspirated obstruents in the world's languages are stops and affricates, aspirated fricatives such as , or have been documented in Korean, though these are allophones of other phonemes. Similarly, aspirated fricatives and even aspirated nasals, approximants, and trills occur in a few Tibeto-Burman languages, in some Oto-Manguean languages, in the Hmongic language Hmu, and in the Siouan language Ofo. Some languages, such as Choni Tibetan, have as many as four contrastive aspirated fricatives , and .

Voiced consonants with voiceless aspiration

True aspirated voiced consonants, as opposed to murmured (breathy-voice) consonants such as the that are common among the languages of India