Paralinguistic phonetics in the wider sense concerns those phenomena in speech that do not belong to language and its arbitrary conventional code, but which nevertheless play an important rôle in speech communication as a biological and social phenomenon. Here belongs the study of the physiological and acoustic differences that can be observed between linguistically identical utterances produced by speakers as a function of their age, sex, and the type of phonation, vocal effort and speech rate they choose, as well as how speech is affected by emotions and other factors. The mentioned factors affect to a high degree also such acoustic properties as the formant frequencies, which are of the utmost importance for the perception of the linguistic-phonetic quality of speech sounds. An important aim within this field consists in describing and explaining man's capacity to perceptually separate the different types of information in speech signals - linguistic, expressive, organic, and perspectival - from each other.
The study of conventionalized features of speech that have a paralinguistic origin can also be considered to belong to this field of study. Such features exist in the lexicon (onomatopoeia and sound symbolism) as well as in the prosody of languages.
The results of studies in paralinguistic phonetics can, among other things, be put to use in technological applications such as speech synthesis in order to simulate paralinguistic variation and in automatic recognition of speech not only in order to recognize the paralinguistic information, but also in order to recognize the linguistic information without being misled by the paralinguistic variation.
Separation of linguistic and other information in speech