Prosodic unit

In linguistics, a prosodic unit is a segment of speech that occurs with specific prosodic properties. These properties can be those of stress, intonation (a single pitch and rhythm contour), or tonal patterns. Prosodic units occur at a hierarchy of levels, from the syllable, the metrical foot and phonological word to the intonational unit (IU) and to a complete utterance. However, the term is often restricted to intermediate levels which do not have a dedicated terminology. Prosodic units do not generally correspond to syntactic units, such as phrases and clauses; it is thought that they reflect different aspects of how the brain processes speech, with prosodic units being generated through on-line interaction and processing, and with morphosyntactic units being more automated. Prosodic units are characterized by several phonetic cues, such as a coherent pitch contour. Breathing, both inhalation and exhalation, only occurs at the boundaries (pausa) between higher units. Several short contours may carry an additional overall gradual decline in pitch and slowing of tempo; this larger unit is termed a declination unit (DU). At the boundaries (pauses) between declination units, the pitch and tempo reset; for this reason the final one of the shorter internal contours is said to have final prosody, whereas the others are said to have continuing prosody. These two levels of the hierarchy may be schematized as follows: {| class=wikitable ! colspan=4 | Declination unit |- | continuing IU, || continuing IU, || continuing IU, || final IU. |} In English orthography, a continuing prosodic boundary may be marked with a comma (assuming the writer is using commas to represent prosody rather than grammatical structure), while final prosodic boundaries may be marked with a full stop (period). The International Phonetic Alphabet has symbols (single and double pipes) for "minor" and "major" prosodic breaks. Since there are more than two levels of prosodic units, the use of these symbols depends on the structure of the language and which information the transcriber is attempting to capture.