Phonation
The term phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Phoneticians in other subfields, such as linguistic phonetics, call this process voicing, and use the term phonation to refer to any oscillatory state of any part of the larynx that modifies the airstream, of which voicing is just one example. Voiceless and supra-glottal phonations are included under this definition.
European language examples[edit]
In languages such as French and Portuguese, all obstruents occur in pairs, one modally voiced and one voiceless: [b] [d] [g] [v] [z] [ʒ] → [p] [t] [k] [f] [s] [ʃ].
In English, every voiced fricative corresponds to a voiceless one. For the pairs of English stops, however, the distinction is better specified as voice onset time rather than simply voice: In initial position, /b d g/ are only partially voiced (voicing begins during the hold of the consonant), and /p t k/ are aspirated (voicing begins only well after its release). Certain English morphemes have voiced and voiceless allomorphs, such as: the plural, verbal, and possessive endings spelled -s (voiced in kids /kɪdz/ but voiceless in kits /kɪts/), and the past-tense ending spelled -ed (voiced in buzzed /bʌzd/ but voiceless in fished /fɪʃt/).
A few European languages, such as Finnish, have no phonemically voiced obstruents but pairs of long and short consonants instead. Outside Europe, the lack of voicing distinctions is common; indeed, in Australian languages it is nearly universal. In languages without the distinction between voiceless and voiced obstruents, they are realized as voiced in voiced environments, such as between vowels, and voiceless elsewhere.