that the terms prenasalization and postnasalization are normally used only in languages where these sounds are phonemic: that is, not analyzed into sequences of plosive plus nasal. Airstream mechanism Stops may be made with more than one airstream mechanism. The normal mechanism is pulmonic egressive, that is, with air flowing outward from the lungs. All languages have pulmonic stops. Some languages have stops made with other mechanisms as well: ejective stops (glottalic egressive), implosive stops (glottalic ingressive), or click consonants (lingual ingressive). Tenseness A fortis plosive is produced with more muscular tension than a lenis plosive. However, this is difficult to measure, and there is usually debate over the actual mechanism of alleged fortis or lenis consonants. There are a series of plosives in the Korean language, sometimes written with the IPA symbol for ejectives, which are produced using "stiff voice", meaning there is increased contraction of the glottis than for normal production of voiceless plosives. The indirect evidence for stiff voice is in the following vowels, which have a higher fundamental frequency than those following other plosives. The higher frequency is explained as a result of the glottis being tense. Other such phonation types include breathy voice, or murmur; slack voice; and creaky voice. Transcription The following plosives have been given dedicated symbols in the IPA. English Variations Many subclassifications of plosives are transcribed by adding a diacritic or modifier letter to the IPA symbols above. See also Continuant (the opposite of a stop) List of phonetics topics Pop filter Nonexplosive stop References Further reading Ian Maddieson, Patterns of Sounds, Cambridge University Press, 1984. External links Bibliotheca Phonetica, Karger, Basel, 1968 Manner of articulation