Tilt is a phonetic model of intonation that represents intonation as a sequence of continuously parameterised events.

The tilt library is a set of functions which analyses, synthesizes and manipulates tilt representations.

Theoretical Overview

The basic unit in the tilt model is the intonational event. Events occur as instants with nothing between them, as opposed to segmental based phenomena where units occur in a contiguous sequence. The basic types of intonational event are pitch accents and (following the popular terminology) boundary tones. Pitch accents (denoted by the letter a) are F0 excursions associated with syllables which are used by the speaker to give some degree of emphasis to a particular word or syllable. In the tilt model, boundary tones (b) are rising F0 excursions which occur at the edges of intonational phrases and as well as giving the hearer a cue as to the end of the phrase, can also signal effects such as continuation and questioning. A combination event ab occurs when a pitch accent and boundary tone occur so close to one another that only a single pitch movement is observed. There are different kinds of pitch accents and boundary tones: the choice of pitch accent and boundary tone allows the speaker to produce different global intonational tunes which can indicate questions, statements, moods etc to the hearer.

Schematic F0 representation

tilt-f0-representation shows a Schematic representation of F0, intonational event relation and segment relation in the Tilt model. The linguistically relevant parts of the F0 contour, which correspond to intonational events, are circled. The events, labelled a for pitch accent and b for boundary are linked to the syllable nuclei of the syllable relation. Note that every event is linked to a syllable, but some syllables do not have events.

Unlike traditional intonational phonology schemes