ITU-T P.807 PDF

This Recommendation describes a subjective testing methodology for assessing speech intelligibility in communications settings, systems and devices. The ITU-T P.807 test methodology has been tested and was found to be appropriate for assessing speech intelligibility of telecommunications systems (e.g., speech codecs), including channel impairments and background noise conditions and for terminals and devices (e.g., handsets, intercom systems). It is designed for use with naive subjects and requires little in the way of specialized equipment or software. The method applies to word intelligibility and does not address intelligibility of phrases or sentences. The method described here applies to North American English. However, the method could be adapted to other languages or dialects taking into account the appropriate set of distinctive features for the language.