aspiration

In phonetics, an escape of unvoiced breath following the release of a plosive consonant, as in English ‘pin’, ‘tin’, ‘kin’, in which the aspirated initial /p/, /t/, /k/ differs from the unaspirated sounds used after /s/, as in ‘spin’, ‘stiff’, ‘skin’.

In French and many other languages, plosives are usually not aspirated. In Hindi, aspirated and unaspirated plosives are phonemically contrastive, as with /ph/ and /p/ (see phoneme); there are also voiced aspirated plosives contrasted with voiced unaspirated ones, as with /bh/ and /b/.

The noun ‘aspirate’ refers also to the sound of English /h/, an unvoiced glottal fricative. The term ‘aspiration’ is also applied by extension to certain cases where a historically pronounced /h/ is now silent, as in French; and even to consonants that are merely spelt with an h, as Welsh ph (/f/), th, ch. In classical Greek aspiration is indicated by a rough breathing (a mark placed above an initial vowel letter or r).