Phonetics and Phonology
Airstreams
Egressive Pulmonic Airstream:
The majority of human sounds are produced by an egressive pulmonic airstream. This movement describes an outgoing airstream produced by the lungs and is regarded as the only airstream mechanism that uses lung air.
All English sounds (both consonants and vowels) are produced by an egressive pulmonic air-stream mechanism, because we speak while we expel air from our lungs (this type of airstream mechanism is also common in other European languages).
Egressive Glottalic Airstream:
In other languages such as African languages, speech sounds are produced by a different air-stream. In this case, the air is used in the mouth to produce speech. Therefore, the air is pushed up from the glottis and makes the air move outwards. This sound is called ejective (represented in the IPA as [p’], voiceless, e.g. pin). Ejectives are not common in European languages but they are common in the native languages of North America, particularly in the Pacific Northwest.
Ingressive Glottalic Airstream:
This airstream describes a movement, initiated by the larynx in which air is going inwards by the glottis, and the sound is implosive (voiced bilabial implosive or voiced velar implosive). None of these airstreams occur in English !
Ingressive Velaric Airstream:
The tongue pushes the air against the velum. As a result, the air is stopped from moving further back. Therefore, a rest of air is drawn into the mouth further forward, and the closure with the tongue is released to make an oral click sound. The best-known click languages that are made of ingressive mouth air are Zulu and Xhosa (South African languages) both can be of voiced or voiceless sounds.
Have a look on this youtube-link to get an idea of how click-languages sound: http://www.youtube.com/watch?v=c246fZ-7z1w
In English, the click sound (voiceless, dental click, see the IPA symbol) is used to indicate annoyance or disapproval. The spelling is “tut-tut” (which is an English verb). Another click sound, called “gee-up” is used to make a horse move faster (voiceless, alveolar-lateral click, see the IPA symbol). Another click sound is used to imitate the "clip-clop" sound of a horse’s hooves (voiceless post-alveolar).
Activity: Breathe in and out. Then say /a:/ as in PALM. Hold it for long as you can. Now try making the same noise on an ingressive airstream. Ingressive air is sometimes used while sobbing or being out of breath.