Our knowledge-based societies in the information age are highly dependent on efficient verbal communication. Today most people have employments which rely on their communication competence. Consequently, communication disorders became a worldwide socio-economic factor. To increase the quality of life on one hand and to keep the economic costs under control on the other, new medical strategies are needed to prevent communication disorders, enable early diagnosis and eventually treat and rehabilitate people concerned.

The key issue for communication is phonation, a complex process of voice production taking place in the larynx. Based on aeroacoustic principles, the sound is generated by the pulsating air jet and supra-glottal turbulent structures. The laryngeal sound is further filtered and amplified by the supra-glottal acoustic resonance spaces, radiated at the lips and perceived as voice. There is no doubt that the possibility to produce voice is crucial for human communication, although many people do not realize this until they lose their voice temporarily, e.g. due to common respiratory inflammations.