Nasalance is a measure of the degree of
velopharyngeal
The velopharyngeal fricatives, also known as the posterior nasal fricatives, are a family of sounds produced by some children with speech disorders, including some with a cleft palate, as a substitute for sibilants (in English, ), which canno ...
opening in voiced speech formed by computing the ratio of the amplitude of the acoustic energy at the
nares, A
n, to amplitude of the acoustic energy at the mouth, A
m. The term ''nasalance'' usually refers to this ratio as a percentage,
:
and thus may be more properly expressed as ''
percent
In mathematics, a percentage () is a number or ratio expressed as a fraction of 100. It is often denoted using the ''percent sign'' (%), although the abbreviations ''pct.'', ''pct'', and sometimes ''pc'' are also used. A percentage is a dime ...
nasalance''. The term originated in the work of Fletcher and his associates
[R.J. Baken, Robert F. Orlikoff. ''Clinical Measurement of Speech and Voice'' San Diego: Singular, 2000] and is now implemented in a number of commercially available devices. There are small differences in the manner in which nasalance is computed in various devices, and differences
in the manner in which the oral and nasal acoustic energies are separated physically, as by a hard separator plate held against the upper lip vs. a two-chamber
pneumotachograph mask. However, there have been no conclusive studies of the effect of these differences on a relevant underlying physical variable, such as the area of the velopharyngeal opening.
See also
*
Nasalization
In phonetics, nasalization (or nasalisation in British English) is the production of a sound while the velum is lowered, so that some air escapes through the nose during the production of the sound by the mouth. An archetypal nasal sound is .
...
*
Nasality
References
Human voice
Nasalization
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