ISO 24620-3:2021 provides basic principles and a methodology for establishing a specification for designing and constructing a formally defined, or controlled, system of oral communication that avoids or filters out phonetic interferences and confusions between words of the same language and between languages. The system is both abstracted from, and contextually situated in, the domains of industry, business or other technologies.

This document deals only with oral communication between native speakers, or non-native speakers, or a native speaker and a non-native speaker, who can be disturbed due to different phenomena, such as phoneme confusion, phonetic interferences and confusions between words (for example: homophony, quasi-homophony or co-articulation) of the same language and/or different languages and the resulting ambiguities due, for example, to multilingual communication or stressful situations. This document deals with speakers and listeners without speech or hearing impediments^[16], and does not include sign languages which have a phonological system equivalent to the system of sounds in spoken languages^[23].

Foreseen applications are essentially in safety critical applications using human oral communication. This document is also applicable to other domains involving, for example, training and evaluation procedures and robots.