Phonation is the process by which the voice box (larynx) makes sounds. Depending upon the sub-field of phonetics, it is distingushed into two groups. Phonation may refer to any manipulation of the vocal stream by the larynx, or may refer only to the quasi-periodic vibrations of the vocal chords that produces voiced sounds. It also includes breathy voice and creaky voice where the phonetic features gets affected by the larynx.
The larynx is also responsible for glottal sounds such as glottal stop, for example “uh-oh”, which is pronounced between the vowels.
Phoneticians who study speech production and laryngeal anatomy often take phonation as quasi-periodic vibration of the vocal chords. By placing your finger on the front of your throat, you can tell if a sound has this type of phonation. A voiced sound is produced when the vocal chords vibrate during speech.
Voiced sounds include all nasal sounds and vowels in English, as well as consonants. For example, V, B, Z, D and G. The voiceless counterparts of these consonants such as F, P, S, T and K differ from their voiced versions. They lack the vibration of the vocal chords.
Some languages have specific voice distinctions than simply voiceless and voiced. Several linguists use phonations to refer to any form of sound manipulation by the glottis. Few languages have laryngealized sounds or creaky-voiced due to tense vocal chords. Also minimal tension in the vocal chords produces murmured sounds or breathy-voiced.
Some other languages use slack voice with more tension than a murmured voice but less then a voiced sound. Some include stiff voice with tension of the vocal chords lying between that required for a laryngealized sound and that required for a voiced sound.
