Discussion centred on the healthy voice.

Production of the human voice is a complex function requiring fine muscular control and co-ordination. Sound is produced by the vibration of the vocal folds (or cords as they are more commonly referred to) and this raw sound is controlled through the muscles of the larynx, mouth and tongue to produce our voices, be they speaking, singing or making a noise. The vibration of the vocal folds is dependant on several factors - the mass, tension and length of the vocal folds, the elasticity of the tissues in the larynx and the pressure of air generated by the lungs. This delicate balance of functions is what creates our individual voice. Our voice is also an expression of our identity and inner being and any vocal changes may not just affect us physically but also psychologically. In fact the voice can also be an indicator of our state of health.

The vocal folds will vibrate quicker in higher pitched voices than in lower voices. Hence the vocal cords from an adult female will vibrate at approx 200 vibrations per second (hertz) whereas an adult male will have a vibration figure of approx 100 hertz. A new born baby will have a vibration rate of approx 450 hertz. In the female, the vocal cords are marginally shorter than in the male which contributes to the figures above. For each doubling of the hertz value the pitch is raised an octave. Resonance of the voice is formed by the use of the vocal cavity. The tongue, palate and uvula move intricately within the space controlling and directing the vibrating air around the vocal cavity creating frequencies/sound waves of differing lengths and therefore audible sounds.

Many factors contribute to produce our voices and the delicate balance of functions can be vulnerable to changes that, however slight, can affect the voice and in turn, the identity we present to the outside world. Our immediate and judgemental perception of the speaking voice illustrates the assumptions and information we draw from the way someone speaks.

Describing the voice is difficult. One person's 'hoarse' is another person's 'harsh'. It is an area that has inherent difficulties. There are several quantitative methods of assessing the voice through instrumentation, but few qualitative methods available that have a clear, useable and reliable application. Christina describes a method called perceptual voice analysis which was developed by a team of research scientists at St Margaret's University College, Edinburgh led by Dr Janet Beck and Professor John Laver. This system has brought about an equal and recognisable way of assessing voice. It is an area that I will explore on my forthcoming visit to Edinburgh.