In the study of prosodic aspects of speech it is usual to distinguish between auditory measures (subjective impressions produced in the mind of the listener) and acoustic measures (physical properties of the sound wave that may be measured objectively). Auditory and acoustic measures of prosody do not correspond in a linear way. Most studies of prosody have been based on auditory analysis using auditory scales.
There is no agreed number of prosodic variables. In auditory terms, the major variables are
in acoustic terms, these correspond reasonably closely to
Different combinations of these variables are exploited in the linguistic functions of intonation and stress, as well as other prosodic features such as rhythm, tempo and loudness. Additional prosodic variables have been studied, including voice quality and pausing.
Prosodic features are said to be suprasegmental, since they are properties of units of speech larger than the individual segment (though exceptionally it may happen that a single segment may constitute a syllable, and thus even a whole utterance, e.g. "Ah!"). It is necessary to distinguish between the personal, background characteristics that belong to an individual’s voice (for example their habitual pitch range) and the independently variable prosodic features that are used contrastively to communicate meaning (for example, the use of changes in pitch to indicate the difference between statements and questions). Personal characteristics are not linguistically significant. It is not possible to say with any accuracy which aspects of prosody are found in all languages and which are specific to a particular language or dialect.