Voice and speech quality perception is a comparably young branch of mainly psycho-acoustics, metrology and linguistics. It deals with all processes that are connected with assessing the auditory quality of voice and speech. Isolated questions within voice and speech quality assessment have of course been dealt with for long mainly in phonetics, linguistics and related fields such as psychology and the cognitive sciences. However, these disciplines only had a limited interest in investigating and understanding the preconditions and processes of voice and speech quality perception itself. They were far more interested in using the results of voice and speech assessments to enhance their knowledge of the development and function of voice, speech and language and/or to increase their understanding of a human being's communicative ability. Voice and speech quality were therefore primarily a means to an end, not the purpose itself.

As part of the steady progress being made in the engineering context of information and telecommunication techniques, mainly speech quality assessment has gained in importance over the last years, particularly in speech technology. Even in this case the main interest was, and remains, to employ speech quality assessment as a means of releasing a further aim: Speech technology engineers require results from voice and speech quality assessments and measurements so that they can make certain statements on the product quality they are aiming to achieve in their individual R&D projects. Speech quality assessments are expected to fulfil certain requirements - they must make reliable and meaningful data available...