2.1.4 Consonants

Most consonants have a closure or stricture in the vocal tract which creates noise components. Depending on the location and manner of this obstruction different consonants can be distinguished from one another. Especially if the consonant is voiced, the respective cavities may act as resonance chambers multiplying its fundamental frequencies produced in the larynx.

Consonants are, in contrast to vowels, extremely different in regards to their acoustic characteristics and can basically be divided into six categories: plosives, nasals, fricatives, approximants, laterals and affricates. Due to the various ways they are produced, each type of consonant can be analysed in reference to consonant specific features. For example we can take a look at the formant frequencies of voiced consonants. Or we can measure the frequencies of fricatives to get information about the constriction of the vocal folds (cf. Harrington 1997).

In actual speech, consonants and vowels flow into each other and so the aperiodic waves of the consonants and the periodic waves of the vowels superimpose on each other. This phase is called transition.

The so called voice onset time is of particular interest within the scope of the acoustic investigation of consonants. It describes the time between the release of a stop closure, and the onset of voicing for a following voiced segment. We can measure the voice onset time only with plosives. “Voice onset time is not strictly speaking a descriptive label, but rather a physical scale along which the realization of stops (occurring before voiced sounds) can be positioned.” (Docherty 1992: 13).

Created with the Personal Edition of HelpNDoc: Free Web Help generator