Aspiration (phonetics)
phonetics, aspiration is the strong burst of air that accompanies the release of some stop consonants. To hear and feel the difference between the aspirated and the unaspirated sound, put your hand in front of your mouth and say key and then ski. The k in Key is aspirated; in ski, it is unaspirated.
English voiceless stops are aspirated when they begin a stressed syllable (as in pen, ten, Ken), but this aspiration is not distinctive (they also have unaspirated variants in other positions). In many languages, such as Hindi/Urdu, Mandarin, Korean, Icelandic and Ancient Greek, /t/ and /tʰ/ are different phonemes altogether.
Basel German has unaspirated /p t k/ and aspirated /pʰ tʰ kʰ/; the latter series may be viewed as clusters. Icelandic has pre-aspirated /hp ht hk/; some scholars interpret these as clusters. /b d g/ are normally also voiceless in Danish and most Southern varieties of German. Traditionally, they are transcribed as <b d g> by scholars (especially in Danish linguistics), even though what distinguishes them from their "fortis" counterparts <p t k> is their lack of aspiration rather than their voicing (which is usually absent).
