Voicelessness

Voicelessness is a term from the linguistic sub-discipline of phonetics and means that the vocal folds are not involved in the articulation of a sound. In the case of voiceless articulation, the vocal folds are so far apart that the air stream coming from the lungs can flow unhindered through the glottis and thus no sound is produced. In contrast, with voiced sounds, a tone with a specific timbre is formed by the vocal folds. Voiced sounds, especially sonorants, are characterized by this sound, while unvoiced sounds are predominantly noises.

Voiceless sounds are usually just consonants. In German these are

• the unvoiced series of fricatives, which are [f], [s], [ʃ], [ç], [x], [χ] and [h].
• and the unvoiced series of closure sounds (plosives), which are [p], [t] [k] and [ʔ].

Word- or syllable-final vowels can also lose their voicing, e.g. in Latvian, Japanese or European Portuguese.

In the International Phonetic Alphabet, voicelessness of a sound is indicated by the IPA character 402 if the sound in question does not have its own character, such as [f]. The glyph used is an underset ring (IPA number 402A, Unicode COMBINING RING BELOW U+0325), for example [n̥] (voiceless alveolar nasal), or an overset ring (IPA number 402B, Unicode COMBINING RING ABOVE U+030A) if the base character has descender, for example [ŋ̊] (voiceless velar nasal).

In the pictorial representation of sounds (spectrogram), as is common in acoustics and phonetics, the absence of a periodic component indicates a voiceless sound. Here the so-called Voice Onset Time (abbreviated VOT) is of importance. The VOT is the time interval between the onset of the sound (due to the release of the closure in closure and fricative sounds) and the onset of vocal fold vibration, i.e. the onset of a tone. If the vocal sound starts after the onset of the sound, it is a positive VOT value and the sound is judged to be voiceless.