Speech melody as articulatorily implemented communicative functions

Abstract

The understanding of speech melody, i.e., pitch variations related to tone and intonation, can be improved by simultaneously taking into consideration two basic facts: that speech conveys communicative meanings, and that it is produced by human articulators. Communicative meanings, as I will argue, are conveyed through a set of separate functions that are realized by an articulatory system with various biophysical properties. These properties make it unlikely that the melodic functions are encoded directly in terms of invariant surface acoustic forms. Rather, the encoding is likely done through the manipulation of a limited number of articulatorily operable parameters that may be considered as the phonetic primitives. Four such primitives can be recognized for speech melody: local pitch targets, pitch range, articulatory strength and duration. The values of the melodic primitives are specified by a set of encoding schemes, each associated with a particular communicative function. The encoding schemes are distinct from each other in the manner of controlling the melodic primitives, which allows multiple communicative functions to be conveyed in parallel. The communicative functions are ultimately converted to continuous, detailed surface acoustic patterns through an articulatory process of syllable-synchronized sequential target approximation, which takes the melodic primitives specified by the encoding schemes as the control parameters. This view of speech melody is summarized into a comprehensive model of tone and intonation, namely, the parallel encoding and target approximation (PENTA) model.